Perpetual benchmark thread... - Page 15

James Heinrich · 2008-09-26, 01:32

No matter how you slice it, 32-bit versions of XP and Vista are capped at 4GB total, and from that maximum you have to carve out reserved memory for hardware:

Quote:

Due to an architectural decision made long ago, if you have 4GB of physical RAM installed, Windows is only able to report a portion of the physical 4GB of RAM (ranges from ~2.75GB to 3.5GB depending on the devices installed, motherboard's chipset & BIOS).

This behavior is due to "memory mapped IO reservations". Those reservations overlay the physical address space and mask out those physical addresses so that they cannot be used for working memory. This is independent of the OS running on the machine.

Significant chunks of address space below 4GB (the highest address accessible via 32-bit) get reserved for use by system hardware:

• BIOS – including ACPI and legacy video support

• PCI bus including bridges etc.

• PCI Express support will reserve at least 256MB, up to 768MB depending on graphics card installed memory

What this means is a typical system may see between ~256MB and 1GB of address space below 4GB reserved for hardware use that the OS cannot access. Intel chipset specs are pretty good at explaining what address ranges gets reserved by default and in some cases call out that 1.5GB is always reserved and thus inaccessible to Windows.

So if you're luckly, you might get away with as much as 4GB - ~300MB = ~3.7GB; if you're unlucky you might end up with 4GB - ~1500MB = ~2.5GB.

petrw1 · 2008-09-26, 02:29

... so I accept that I won't have access to 4GB until the day I upgrade to a 64 bit OS that handles it ... and so if I understand GIMPS correctly:

a) This does not in anyway restrict or slow down LL or DC tests
b) P1 Factoring is not resticted or affected
c) I will not be able to do ECM with b1/b2 over about 3.2 GB

Am I close?
Did I miss anything significant re: GIMPS or any of the sub-projects?

I plan to, and want to without restrictions, run Prime95 (and possibly some other related software) 24X7 on all 4 cores.

James Heinrich · 2008-09-26, 10:08

a) There is no significant speed difference in LL testing between 32- and 64-bit versions of Prime95 (see my benchmarks page, you can see a direct comparison between Q6600 @ 3.4GHz in 32-bit and 64-bit Prime95 v25.6).

a2) Not mentioned in your list of question, but at the above link you'll notice that TF is noticably faster on 64-bit up to 2^63 (see this thread for all sorts of detailed numbers and pretty graphs comparing 32- and 64-bit Prime95 performance).

b,c) P-1 (presumably ECM is similar) works better with more memory (works faster, so can spend more time processing to higher B1/B2, so has higher chance of finding factors). 32-bit Prime95 you'll be limited to <2GB. 64-bit should in theory not be limited, and if I recall correctly the 64-bit version of v24.x does work fine, but be aware that v25.6 x64 is buggy when >1800MB of RAM is allocated (e.g. this thread, posts 329-333).
Prime95 will prevent you from assigning more than 90% of the installed physical memory to itself; I believe on 32-bit Prime95 that would be the lesser of 90% of (physical RAM or 2GB), so for systems with 2GB+ that would be 1843MB.

henryzz · 2008-09-26, 16:27

is it possible for an OC to be stable with anything u throw at it in win32 but to crash in win64

Xyzzy · 2008-09-27, 02:16

Quote:

Am I close?

We run 64-bit on our dual core and 32-bit on our quad core. Both have 4GiB memory each. Both run exactly the same speed in most programs whether we have 64-bit or 32-bit Vista loaded. A few programs run faster with 64-bit Vista. 64-bit vista programs tend to use more memory.

It is kind of neat to look at the system screen and see all 4GiB in use.

We are waiting for something like this to drop in price someday.

James Heinrich · 2008-09-27, 10:42

Quote:

Originally Posted by Xyzzy

It is kind of neat to look at the system screen and see all 4GiB in use.

Vista32 original edition will show actual available RAM in system properties (e.g. 3.2GB out of 4GB installed). Service Pack 1 does the less-useful thing of showing the physically installed RAM (e.g. 4GB) and no how much can actually be used.

Quote:

Originally Posted by Xyzzy

We are waiting for something like this to drop in price someday.

Presumably your two systems are not laptops (you linked to 667MHz laptop RAM). Desktop 2x4GB 800MHz RAM is available and not unreasonably priced (e.g. CAD$220).

Xyzzy · 2008-09-27, 11:28

Quote:

Presumably your two systems are not laptops (you linked to 667MHz laptop RAM). Desktop 2x4GB 800MHz RAM is available and not unreasonably priced (e.g. CAD$220).

The quad core is a desktop and the dual core is a laptop.

The desktop has an Intel motherboard that has "issues" with more than 4GiB.

Jeff Gilchrist · 2008-10-03, 10:53

Processor: Q9550 @ 3.4 GHz (overclocked)
Motherboard: ASUS Maximus II Formula
OS: Vista 64-bit
Memory: 4GB DDR2-1066
mprime: 25.6 build 6 Prime95 Windows64

Code:

[Fri Oct 03 06:49:07 2008]
Compare your results to other computers at http://www.mersenne.org/bench.htm
Intel(R) Core(TM)2 Quad  CPU   Q9550  @ 2.83GHz
CPU speed: 3399.78 MHz, 4 cores
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2
L1 cache size: 32 KB
L2 cache size: 6144 KB
L1 cache line size: 64 bytes
L2 cache line size: 64 bytes
TLBS: 256
Prime95 64-bit version 25.6, RdtscTiming=1
Best time for 768K FFT length: 11.950 ms.
Best time for 896K FFT length: 14.417 ms.
Best time for 1024K FFT length: 16.414 ms.
Best time for 1280K FFT length: 20.547 ms.
Best time for 1536K FFT length: 25.378 ms.
Best time for 1792K FFT length: 30.163 ms.
Best time for 2048K FFT length: 33.525 ms.
Best time for 2560K FFT length: 44.095 ms.
Best time for 3072K FFT length: 54.028 ms.
Best time for 3584K FFT length: 64.614 ms.
Best time for 4096K FFT length: 72.135 ms.
Best time for 5120K FFT length: 91.620 ms.
Best time for 6144K FFT length: 111.167 ms.
Best time for 7168K FFT length: 134.731 ms.
Best time for 8192K FFT length: 147.020 ms.
Timing FFTs using 2 threads.
Best time for 768K FFT length: 6.330 ms.
Best time for 896K FFT length: 7.557 ms.
Best time for 1024K FFT length: 8.723 ms.
Best time for 1280K FFT length: 10.577 ms.
Best time for 1536K FFT length: 13.044 ms.
Best time for 1792K FFT length: 15.573 ms.
Best time for 2048K FFT length: 17.517 ms.
Best time for 2560K FFT length: 22.765 ms.
Best time for 3072K FFT length: 27.971 ms.
Best time for 3584K FFT length: 33.330 ms.
Best time for 4096K FFT length: 37.173 ms.
Best time for 5120K FFT length: 47.660 ms.
Best time for 6144K FFT length: 58.364 ms.
Best time for 7168K FFT length: 69.988 ms.
Best time for 8192K FFT length: 77.260 ms.
Timing FFTs using 3 threads.
Best time for 768K FFT length: 7.015 ms.
Best time for 896K FFT length: 7.943 ms.
Best time for 1024K FFT length: 11.759 ms.
Best time for 1280K FFT length: 8.901 ms.
Best time for 1536K FFT length: 10.771 ms.
Best time for 1792K FFT length: 12.758 ms.
Best time for 2048K FFT length: 14.379 ms.
Best time for 2560K FFT length: 18.919 ms.
Best time for 3072K FFT length: 23.325 ms.
Best time for 3584K FFT length: 27.434 ms.
Best time for 4096K FFT length: 31.147 ms.
Best time for 5120K FFT length: 38.022 ms.
Best time for 6144K FFT length: 46.252 ms.
Best time for 7168K FFT length: 55.382 ms.
Best time for 8192K FFT length: 61.572 ms.
Timing FFTs using 4 threads.
Best time for 768K FFT length: 6.261 ms.
Best time for 896K FFT length: 7.016 ms.
Best time for 1024K FFT length: 10.224 ms.
Best time for 1280K FFT length: 7.677 ms.
Best time for 1536K FFT length: 8.970 ms.
Best time for 1792K FFT length: 10.457 ms.
Best time for 2048K FFT length: 11.916 ms.
Best time for 2560K FFT length: 15.396 ms.
Best time for 3072K FFT length: 18.805 ms.
Best time for 3584K FFT length: 22.152 ms.
Best time for 4096K FFT length: 25.352 ms.
Best time for 5120K FFT length: 31.265 ms.
Best time for 6144K FFT length: 37.550 ms.
Best time for 7168K FFT length: 44.517 ms.
Best time for 8192K FFT length: 50.371 ms.
Best time for 58 bit trial factors: 2.503 ms.
Best time for 59 bit trial factors: 2.480 ms.
Best time for 60 bit trial factors: 2.843 ms.
Best time for 61 bit trial factors: 2.979 ms.
Best time for 62 bit trial factors: 3.398 ms.
Best time for 63 bit trial factors: 4.362 ms.
Best time for 64 bit trial factors: 4.729 ms.
Best time for 65 bit trial factors: 5.244 ms.
Best time for 66 bit trial factors: 5.193 ms.
Best time for 67 bit trial factors: 5.173 ms.

S00113 · 2008-10-03, 12:11

The Asus Eee PC901 is not a lightning. I am particularly surprised about the result for 62 and 63 bit factoring, and repeated the benchmark to verify.

Code:

Intel(R) Atom(TM) CPU N270   @ 1.60GHz
CPU speed: 1679.77 MHz, with hyperthreading
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2
L1 cache size: unknown
L2 cache size: 512 KB
L1 cache line size: unknown
L2 cache line size: 64 bytes
Prime95 32-bit version 25.6, RdtscTiming=1
Best time for 768K FFT length: 204.905 ms.
Best time for 896K FFT length: 245.989 ms.
Best time for 1024K FFT length: 269.821 ms.
Best time for 1280K FFT length: 350.554 ms.
Best time for 1536K FFT length: 423.340 ms.
Best time for 1792K FFT length: 511.699 ms.
Best time for 2048K FFT length: 563.404 ms.
Best time for 2560K FFT length: 741.110 ms.
Best time for 3072K FFT length: 908.581 ms.
Best time for 3584K FFT length: 1094.337 ms.
Best time for 4096K FFT length: 1204.096 ms.
Best time for 5120K FFT length: 1565.931 ms.
Best time for 6144K FFT length: 1887.129 ms.
Best time for 7168K FFT length: 2283.427 ms.
Best time for 8192K FFT length: 2516.333 ms.
Timing FFTs using 2 threads on 1 physical CPUs.
Best time for 768K FFT length: 207.166 ms.
Best time for 896K FFT length: 249.429 ms.
Best time for 1024K FFT length: 275.451 ms.
Best time for 1280K FFT length: 363.530 ms.
Best time for 1536K FFT length: 441.042 ms.
Best time for 1792K FFT length: 536.902 ms.
Best time for 2048K FFT length: 570.403 ms.
Best time for 2560K FFT length: 757.929 ms.
Best time for 3072K FFT length: 913.659 ms.
Best time for 3584K FFT length: 1115.989 ms.
Best time for 4096K FFT length: 1222.641 ms.
Best time for 5120K FFT length: 1588.970 ms.
Best time for 6144K FFT length: 1936.954 ms.
Best time for 7168K FFT length: 2333.076 ms.
Best time for 8192K FFT length: 2576.393 ms.
Best time for 58 bit trial factors: 19.060 ms.
Best time for 59 bit trial factors: 19.026 ms.
Best time for 60 bit trial factors: 18.985 ms.
Best time for 61 bit trial factors: 19.153 ms.
Best time for 62 bit trial factors: 39.511 ms.
Best time for 63 bit trial factors: 39.585 ms.
Best time for 64 bit trial factors: 22.897 ms.
Best time for 65 bit trial factors: 22.826 ms.
Best time for 66 bit trial factors: 22.771 ms.
Best time for 67 bit trial factors: 22.848 ms.

Jeff Gilchrist · 2008-10-09, 10:09

A Xeon 2.0GHz system with 8 CPUs and 32GB of RAM.

Code:

[Thu Oct  9 05:48:54 2008]
Compare your results to other computers at http://www.mersenne.org/bench.htm
Intel(R) Xeon(R) CPU           E5405  @ 2.00GHz
CPU speed: 1995.13 MHz, 8 cores
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2, SSE4
L1 cache size: 32 KB
L2 cache size: 6 MB
L1 cache line size: 64 bytes
L2 cache line size: 64 bytes
TLBS: 256
Prime95 64-bit version 25.7, RdtscTiming=1
Best time for 768K FFT length: 22.146 ms.
Best time for 896K FFT length: 26.916 ms.
Best time for 1024K FFT length: 30.886 ms.
Best time for 1280K FFT length: 38.894 ms.
Best time for 1536K FFT length: 48.001 ms.
Best time for 1792K FFT length: 57.217 ms.
Best time for 2048K FFT length: 63.896 ms.
Best time for 2560K FFT length: 83.944 ms.
Best time for 3072K FFT length: 102.804 ms.
Best time for 3584K FFT length: 122.359 ms.
Best time for 4096K FFT length: 137.471 ms.
Best time for 5120K FFT length: 174.515 ms.
Best time for 6144K FFT length: 211.218 ms.
Best time for 7168K FFT length: 254.722 ms.
Best time for 8192K FFT length: 279.718 ms.
Timing FFTs using 2 threads.
Best time for 768K FFT length: 16.054 ms.
Best time for 896K FFT length: 18.535 ms.
Best time for 1024K FFT length: 22.839 ms.
Best time for 1280K FFT length: 23.627 ms.
Best time for 1536K FFT length: 28.192 ms.
Best time for 1792K FFT length: 33.012 ms.
Best time for 2048K FFT length: 36.375 ms.
Best time for 2560K FFT length: 46.765 ms.
Best time for 3072K FFT length: 56.702 ms.
Best time for 3584K FFT length: 66.865 ms.
Best time for 4096K FFT length: 74.897 ms.
Best time for 5120K FFT length: 94.475 ms.
Best time for 6144K FFT length: 113.789 ms.
Best time for 7168K FFT length: 136.821 ms.
Best time for 8192K FFT length: 150.591 ms.
Timing FFTs using 3 threads.
Best time for 768K FFT length: 11.290 ms.
Best time for 896K FFT length: 12.675 ms.
Best time for 1024K FFT length: 21.320 ms.
Best time for 1280K FFT length: 16.226 ms.
Best time for 1536K FFT length: 19.596 ms.
Best time for 1792K FFT length: 22.870 ms.
Best time for 2048K FFT length: 25.578 ms.
Best time for 2560K FFT length: 32.713 ms.
Best time for 3072K FFT length: 39.443 ms.
Best time for 3584K FFT length: 46.487 ms.
Best time for 4096K FFT length: 51.982 ms.
Best time for 5120K FFT length: 65.404 ms.
Best time for 6144K FFT length: 79.261 ms.
Best time for 7168K FFT length: 94.797 ms.
Best time for 8192K FFT length: 104.569 ms.
Timing FFTs using 4 threads.
Best time for 768K FFT length: 11.941 ms.
Best time for 896K FFT length: 13.228 ms.
Best time for 1024K FFT length: 20.417 ms.
Best time for 1280K FFT length: 14.052 ms.
Best time for 1536K FFT length: 16.248 ms.
Best time for 1792K FFT length: 18.330 ms.
Best time for 2048K FFT length: 20.813 ms.
Best time for 2560K FFT length: 26.098 ms.
Best time for 3072K FFT length: 31.345 ms.
Best time for 3584K FFT length: 36.886 ms.
Best time for 4096K FFT length: 41.346 ms.
Best time for 5120K FFT length: 51.936 ms.
Best time for 6144K FFT length: 62.601 ms.
Best time for 7168K FFT length: 74.862 ms.
Best time for 8192K FFT length: 83.355 ms.
Timing FFTs using 5 threads.
Best time for 768K FFT length: 10.723 ms.
Best time for 896K FFT length: 11.874 ms.
Best time for 1024K FFT length: 18.265 ms.
Best time for 1280K FFT length: 12.628 ms.
Best time for 1536K FFT length: 14.712 ms.
Best time for 1792K FFT length: 16.855 ms.
Best time for 2048K FFT length: 18.999 ms.
Best time for 2560K FFT length: 23.346 ms.
Best time for 3072K FFT length: 27.518 ms.
Best time for 3584K FFT length: 31.728 ms.
Best time for 4096K FFT length: 35.779 ms.
Best time for 5120K FFT length: 44.055 ms.
Best time for 6144K FFT length: 52.603 ms.
Best time for 7168K FFT length: 62.706 ms.
Best time for 8192K FFT length: 69.609 ms.
Timing FFTs using 6 threads.
Best time for 768K FFT length: 11.016 ms.
Best time for 896K FFT length: 12.232 ms.
Best time for 1024K FFT length: 19.216 ms.
Best time for 1280K FFT length: 12.452 ms.
Best time for 1536K FFT length: 14.440 ms.
Best time for 1792K FFT length: 16.424 ms.
Best time for 2048K FFT length: 18.326 ms.
Best time for 2560K FFT length: 22.395 ms.
Best time for 3072K FFT length: 26.268 ms.
Best time for 3584K FFT length: 30.318 ms.
Best time for 4096K FFT length: 34.400 ms.
Best time for 5120K FFT length: 42.347 ms.
Best time for 6144K FFT length: 50.357 ms.
Best time for 7168K FFT length: 58.599 ms.
Best time for 8192K FFT length: 66.622 ms.
Timing FFTs using 7 threads.
Best time for 768K FFT length: 10.705 ms.
Best time for 896K FFT length: 11.915 ms.
Best time for 1024K FFT length: 18.881 ms.
Best time for 1280K FFT length: 12.066 ms.
Best time for 1536K FFT length: 13.891 ms.
Best time for 1792K FFT length: 15.705 ms.
Best time for 2048K FFT length: 17.513 ms.
Best time for 2560K FFT length: 21.350 ms.
Best time for 3072K FFT length: 25.002 ms.
Best time for 3584K FFT length: 28.904 ms.
Best time for 4096K FFT length: 32.508 ms.
Best time for 5120K FFT length: 39.699 ms.
Best time for 6144K FFT length: 47.257 ms.
Best time for 7168K FFT length: 54.904 ms.
Best time for 8192K FFT length: 62.075 ms.
Timing FFTs using 8 threads.
Best time for 768K FFT length: 10.179 ms.
Best time for 896K FFT length: 11.308 ms.
Best time for 1024K FFT length: 17.562 ms.
Best time for 1280K FFT length: 11.427 ms.
[Thu Oct  9 05:53:56 2008]
Best time for 1536K FFT length: 13.242 ms.
Best time for 1792K FFT length: 14.995 ms.
Best time for 2048K FFT length: 16.732 ms.
Best time for 2560K FFT length: 20.280 ms.
Best time for 3072K FFT length: 23.874 ms.
Best time for 3584K FFT length: 27.299 ms.
Best time for 4096K FFT length: 30.726 ms.
Best time for 5120K FFT length: 37.752 ms.
Best time for 6144K FFT length: 44.930 ms.
Best time for 7168K FFT length: 51.954 ms.
Best time for 8192K FFT length: 58.672 ms.
Best time for 58 bit trial factors: 4.466 ms.
Best time for 59 bit trial factors: 4.457 ms.
Best time for 60 bit trial factors: 4.779 ms.
Best time for 61 bit trial factors: 5.020 ms.
Best time for 62 bit trial factors: 5.897 ms.
Best time for 63 bit trial factors: 7.529 ms.
Best time for 64 bit trial factors: 8.079 ms.
Best time for 65 bit trial factors: 8.638 ms.
Best time for 66 bit trial factors: 8.562 ms.
Best time for 67 bit trial factors: 8.558 ms.

db597 · 2008-10-12, 17:59

Just put together an Intel E5200 today. Running on 667MHz DDR2 (was salvage from an old PC that crashed). Overclocked to 3.3GHz right out of the box. Benchmarks are similar to what a much more expensive E8500 would produce at stock.

Pentium(R) Dual-Core CPU E5200 @ 2.50GHz
CPU speed: 3324.86 MHz
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2
L1 cache size: 32 KB
L2 cache size: 2048 KB
L1 cache line size: 64 bytes
L2 cache line size: 64 bytes
Prime95 32-bit version 24.14, RdtscTiming=1
Best time for 512K FFT length: 8.089 ms.
Best time for 640K FFT length: 10.925 ms.
Best time for 768K FFT length: 13.537 ms.
Best time for 896K FFT length: 15.994 ms.
Best time for 1024K FFT length: 18.759 ms.
Best time for 1280K FFT length: 22.569 ms.
Best time for 1536K FFT length: 27.584 ms.
Best time for 1792K FFT length: 32.777 ms.
Best time for 2048K FFT length: 36.496 ms.
Best time for 2560K FFT length: 48.080 ms.
Best time for 3072K FFT length: 58.762 ms.
Best time for 3584K FFT length: 69.802 ms.
Best time for 4096K FFT length: 78.224 ms.
Best time for 58 bit trial factors: 3.237 ms.
Best time for 59 bit trial factors: 3.222 ms.
Best time for 60 bit trial factors: 3.211 ms.
Best time for 61 bit trial factors: 3.235 ms.
Best time for 62 bit trial factors: 5.267 ms.
Best time for 63 bit trial factors: 5.274 ms.
Best time for 64 bit trial factors: 4.849 ms.
Best time for 65 bit trial factors: 4.812 ms.
Best time for 66 bit trial factors: 4.831 ms.
Best time for 67 bit trial factors: 4.801 ms.

Nelson · 2008-10-18, 16:58

This is not an official benchmark per se it does give hopefully a better understanding of the workings of Threaded Prime95 with a Quad core CPU. Some formatting didn't work well with txt format (see attached file) so I apologize if some areas don't appear as a table. Guess I'll have to get a PDF documenting program.
I have also inserted the most recent Benchmark test as a reference. Timing is however not the same as they are done at different overclocks.

Code:

Compare your results to other computers at http://www.mersenne.org/bench.htm
Intel(R) Core(TM)2 Quad CPU    Q6600  @ 2.40GHz
CPU speed: 3375.63 MHz, 4 cores
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2
L1 cache size: 32 KB
L2 cache size: 4096 KB
L1 cache line size: 64 bytes
L2 cache line size: 64 bytes
TLBS: 256
Prime95 32-bit version 25.6, RdtscTiming=1
Best time for 768K FFT length: 12.623 ms.
Best time for 896K FFT length: 15.127 ms.
Best time for 1024K FFT length: 17.457 ms.
Best time for 1280K FFT length: 21.549 ms.
Best time for 1536K FFT length: 26.301 ms.
Best time for 1792K FFT length: 31.279 ms.
Best time for 2048K FFT length: 34.803 ms.
Best time for 2560K FFT length: 45.811 ms.
Best time for 3072K FFT length: 55.989 ms.
Best time for 3584K FFT length: 66.579 ms.
Best time for 4096K FFT length: 74.470 ms.
Best time for 5120K FFT length: 95.424 ms.
Best time for 6144K FFT length: 115.102 ms.
Best time for 7168K FFT length: 139.981 ms.
Best time for 8192K FFT length: 153.695 ms.
Timing FFTs using 2 threads.
Best time for 768K FFT length: 6.858 ms.
Best time for 896K FFT length: 8.288 ms.
Best time for 1024K FFT length: 9.610 ms.
Best time for 1280K FFT length: 11.722 ms.
Best time for 1536K FFT length: 14.382 ms.
Best time for 1792K FFT length: 17.048 ms.
Best time for 2048K FFT length: 19.326 ms.
Best time for 2560K FFT length: 24.967 ms.
Best time for 3072K FFT length: 30.512 ms.
Best time for 3584K FFT length: 36.076 ms.
Best time for 4096K FFT length: 40.948 ms.
Best time for 5120K FFT length: 52.370 ms.
Best time for 6144K FFT length: 64.151 ms.
Best time for 7168K FFT length: 77.485 ms.
Best time for 8192K FFT length: 87.918 ms.
Timing FFTs using 3 threads.
Best time for 768K FFT length: 7.964 ms.
Best time for 896K FFT length: 9.023 ms.
Best time for 1024K FFT length: 13.073 ms.
Best time for 1280K FFT length: 10.865 ms.
Best time for 1536K FFT length: 13.351 ms.
Best time for 1792K FFT length: 15.803 ms.
Best time for 2048K FFT length: 18.121 ms.
Best time for 2560K FFT length: 22.895 ms.
Best time for 3072K FFT length: 28.057 ms.
Best time for 3584K FFT length: 33.250 ms.
Best time for 4096K FFT length: 37.992 ms.
Best time for 5120K FFT length: 47.462 ms.
Best time for 6144K FFT length: 57.334 ms.
Best time for 7168K FFT length: 70.736 ms.
Best time for 8192K FFT length: 79.907 ms.
Timing FFTs using 4 threads.
Best time for 768K FFT length: 7.064 ms.
Best time for 896K FFT length: 8.061 ms.
Best time for 1024K FFT length: 11.488 ms.
Best time for 1280K FFT length: 9.730 ms.
Best time for 1536K FFT length: 11.916 ms.
Best time for 1792K FFT length: 14.080 ms.
Best time for 2048K FFT length: 16.204 ms.
Best time for 2560K FFT length: 20.631 ms.
Best time for 3072K FFT length: 24.870 ms.
Best time for 3584K FFT length: 29.409 ms.
Best time for 4096K FFT length: 34.202 ms.
Best time for 5120K FFT length: 42.745 ms.
Best time for 6144K FFT length: 51.531 ms.
Best time for 7168K FFT length: 62.554 ms.
Best time for 8192K FFT length: 71.525 ms.
Best time for 58 bit trial factors: 3.193 ms.
Best time for 59 bit trial factors: 3.201 ms.
Best time for 60 bit trial factors: 3.170 ms.
Best time for 61 bit trial factors: 3.161 ms.
Best time for 62 bit trial factors: 5.273 ms.
Best time for 63 bit trial factors: 5.278 ms.
Best time for 64 bit trial factors: 4.906 ms.
Best time for 65 bit trial factors: 4.872 ms.
Best time for 66 bit trial factors: 4.874 ms.
Best time for 67 bit trial factors: 4.858 ms.

nelson

starrynte · 2008-10-19, 03:47

Code:

Intel(R) Pentium(R) 4 CPU 3.00GHz
CPU speed: 3060.56 MHz
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2
L1 cache size: 16 KB
L2 cache size: 1024 KB
L1 cache line size: 64 bytes
L2 cache line size: 128 bytes
TLBS: 64
Prime95 32-bit version 24.14, RdtscTiming=1
Best time for 512K FFT length: 17.214 ms.
Best time for 640K FFT length: 22.350 ms.
Best time for 768K FFT length: 27.172 ms.
Best time for 896K FFT length: 33.198 ms.
Best time for 1024K FFT length: 38.122 ms.
Best time for 1280K FFT length: 46.649 ms.
Best time for 1536K FFT length: 56.462 ms.
Best time for 1792K FFT length: 68.155 ms.
Best time for 2048K FFT length: 76.344 ms.
Best time for 2560K FFT length: 100.902 ms.
Best time for 3072K FFT length: 121.601 ms.
Best time for 3584K FFT length: 147.856 ms.
Best time for 4096K FFT length: 163.470 ms.
Best time for 58 bit trial factors: 9.453 ms.
Best time for 59 bit trial factors: 9.536 ms.
Best time for 60 bit trial factors: 9.343 ms.
Best time for 61 bit trial factors: 9.450 ms.
Best time for 62 bit trial factors: 13.165 ms.
Best time for 63 bit trial factors: 13.158 ms.
Best time for 64 bit trial factors: 15.198 ms.
Best time for 65 bit trial factors: 15.172 ms.
Best time for 66 bit trial factors: 15.356 ms.
Best time for 67 bit trial factors: 15.302 ms.

Hyperthreading enabled, benchmark was run with affinity set to both "cores"
Memory: 3 GB

henryzz · 2008-10-20, 19:19

Quote:

Originally Posted by starrynte

Code:

Intel(R) Pentium(R) 4 CPU 3.00GHz
CPU speed: 3060.56 MHz
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2
L1 cache size: 16 KB
L2 cache size: 1024 KB
L1 cache line size: 64 bytes
L2 cache line size: 128 bytes
TLBS: 64
Prime95 32-bit version 24.14, RdtscTiming=1
Best time for 512K FFT length: 17.214 ms.
Best time for 640K FFT length: 22.350 ms.
Best time for 768K FFT length: 27.172 ms.
Best time for 896K FFT length: 33.198 ms.
Best time for 1024K FFT length: 38.122 ms.
Best time for 1280K FFT length: 46.649 ms.
Best time for 1536K FFT length: 56.462 ms.
Best time for 1792K FFT length: 68.155 ms.
Best time for 2048K FFT length: 76.344 ms.
Best time for 2560K FFT length: 100.902 ms.
Best time for 3072K FFT length: 121.601 ms.
Best time for 3584K FFT length: 147.856 ms.
Best time for 4096K FFT length: 163.470 ms.
Best time for 58 bit trial factors: 9.453 ms.
Best time for 59 bit trial factors: 9.536 ms.
Best time for 60 bit trial factors: 9.343 ms.
Best time for 61 bit trial factors: 9.450 ms.
Best time for 62 bit trial factors: 13.165 ms.
Best time for 63 bit trial factors: 13.158 ms.
Best time for 64 bit trial factors: 15.198 ms.
Best time for 65 bit trial factors: 15.172 ms.
Best time for 66 bit trial factors: 15.356 ms.
Best time for 67 bit trial factors: 15.302 ms.

Hyperthreading enabled, benchmark was run with affinity set to both "cores"
Memory: 3 GB

compared to the core 2 architecture clock to clock ur p4 is about half the speed

petrw1 · 2008-10-20, 19:34

Quote:

Originally Posted by Jeff Gilchrist

Processor: Q9550 @ 3.4 GHz (overclocked)
Motherboard: ASUS Maximus II Formula
OS: Vista 64-bit
Memory: 4GB DDR2-1066
mprime: 25.6 build 6 Prime95 Windows64

Code:

[Fri Oct 03 06:49:07 2008]
Best time for 1024K FFT length: 16.414 ms.
Best time for 2048K FFT length: 33.525 ms.
Best time for 4096K FFT length: 72.135 ms.
Best time for 8192K FFT length: 147.020 ms.
Timing FFTs using 2 threads.
Best time for 1024K FFT length: 8.723 ms.
Best time for 2048K FFT length: 17.517 ms.
Best time for 4096K FFT length: 37.173 ms.
Best time for 8192K FFT length: 77.260 ms.
Timing FFTs using 3 threads.
Best time for 1024K FFT length: 11.759 ms.
Best time for 2048K FFT length: 14.379 ms.
Best time for 4096K FFT length: 31.147 ms.
Best time for 8192K FFT length: 61.572 ms.
Timing FFTs using 4 threads.
Best time for 1024K FFT length: 10.224 ms.
Best time for 2048K FFT length: 11.916 ms.
Best time for 4096K FFT length: 25.352 ms.
Best time for 8192K FFT length: 50.371 ms.

Others have reported that due to other overhead or bottlenecks you can't get 4 cores to have 4 times the throughput as 1 ... HOWEVER ... it strikes me as very unexpected that in your test 3 threads is slower than 2 and even 4 is slower than 2 with the 1024 FFT. Other sizes I extracted show the expected improvement I suppose.

T.Rex · 2008-10-23, 14:43

Hi,

I've got results of mprime on a (prototype) Nehalem 8 cores 2.4 GHz .

I'll not provide detailed results since I do not know yet if it is confidential or not. I'll just focus on mprime scalability.
(Note that there are some errors while allocating memory for some of the FFTs.)

At 8 MB FFT:
For 2 cores, the scalability is about 98.5% (1.97) .
For 4 cores, the scalability is about 82.2% (3.29) .
For 6 cores, the scalability is about 71.0% (4.26) .
For 8 cores, the scalability is about 66.6% (5.33) .
Not so bad.

George,

1) Do you plan to work on a version of Prime95 that will fully take profit of the Nehalem processor ?

2) Are there some limitations within Prime95 about the number of cores ? Is it able to run on a machine with more than 8 cores ?

T.

T.Rex · 2008-10-23, 14:57

Hi,

Here are some complementary results, dealing with the scalability of Glucas (tests done using my "personnal" tricks about Glucas...).
As you can see, the scalability is ... incredible !! Much better than what I saw on our Bull Itanium2 NovaScale machine, I think.

But I need to provide a comparison of Glucas and mprime performance on the same FFT size for 1 core. This comparison is useful because Glucas probably does NOT fill the CPU caches as good as mprime does ! So that it is more scalable but not as powerful... Later.

T.

Exponent: 43112609 .
For 2 cores, the scalability is about 99.4% (1.99) .
For 3 cores, the scalability is about 98.7% (2.96) .
For 4 cores, the scalability is about 98.5% (3.94) .
For 5 cores, the scalability is about 95.5% (4.78) .
For 6 cores, the scalability is about 98.0% (5.88) .
For 7 cores, the scalability is about 92.5% (6.47) .
For 8 cores, the scalability is about 93.6% (7.49) .

Uncwilly · 2008-10-23, 22:18

Quote:

Originally Posted by T.Rex

I've got results of mprime on a (prototype) Nehalem 8 cores 2.4 GHz .

I'll not provide detailed results since I do not know yet if it is confidential or not. I'll just focus on mprime scalability.
(Note that there are some errors while allocating memory for some of the FFTs.)

Which version of mprime? What about parallel through-put? (multiple instances/tasks)

James Heinrich · 2008-10-23, 23:08

Quote:

Originally Posted by petrw1

it strikes me as very unexpected that in your test 3 threads is slower than 2 and even 4 is slower than 2 with the 1024 FFT. Other sizes I extracted show the expected improvement I suppose.

Take a look at my results in this thread (post #5) -- take a look at the attachment and you can see the anomaly for 768, 896 and 1024 FFT sizes (where 2 threads is nearly twice as fast as 1 thread, but 3 threads reverts back to nearly the same time as 1 thread, and 4 threads still isn't as fast as 2). Fortunately for all FFT sizes above 1024 it gets faster (with diminishing returns, of course) as you throw more threads at it.

starrynte · 2008-10-25, 20:08

Quote:

Originally Posted by starrynte

Code:

Intel(R) Pentium(R) 4 CPU 3.00GHz
CPU speed: 3060.56 MHz
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2
L1 cache size: 16 KB
L2 cache size: 1024 KB
L1 cache line size: 64 bytes
L2 cache line size: 128 bytes
TLBS: 64
Prime95 32-bit version 24.14, RdtscTiming=1
Best time for 512K FFT length: 17.214 ms.
Best time for 640K FFT length: 22.350 ms.
Best time for 768K FFT length: 27.172 ms.
Best time for 896K FFT length: 33.198 ms.
Best time for 1024K FFT length: 38.122 ms.
Best time for 1280K FFT length: 46.649 ms.
Best time for 1536K FFT length: 56.462 ms.
Best time for 1792K FFT length: 68.155 ms.
Best time for 2048K FFT length: 76.344 ms.
Best time for 2560K FFT length: 100.902 ms.
Best time for 3072K FFT length: 121.601 ms.
Best time for 3584K FFT length: 147.856 ms.
Best time for 4096K FFT length: 163.470 ms.
Best time for 58 bit trial factors: 9.453 ms.
Best time for 59 bit trial factors: 9.536 ms.
Best time for 60 bit trial factors: 9.343 ms.
Best time for 61 bit trial factors: 9.450 ms.
Best time for 62 bit trial factors: 13.165 ms.
Best time for 63 bit trial factors: 13.158 ms.
Best time for 64 bit trial factors: 15.198 ms.
Best time for 65 bit trial factors: 15.172 ms.
Best time for 66 bit trial factors: 15.356 ms.
Best time for 67 bit trial factors: 15.302 ms.

Hyperthreading enabled, benchmark was run with affinity set to both "cores"
Memory: 3 GB

Code:

Intel(R) Pentium(R) 4 CPU 3.00GHz
CPU speed: 3060.63 MHz, with hyperthreading
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2
L1 cache size: 16 KB
L2 cache size: 1 MB
L1 cache line size: 64 bytes
L2 cache line size: 128 bytes
TLBS: 64
Prime95 32-bit version 25.7, RdtscTiming=1
Best time for 768K FFT length: 25.065 ms.
Best time for 896K FFT length: 30.673 ms.
Best time for 1024K FFT length: 34.442 ms.
Best time for 1280K FFT length: 42.977 ms.
Best time for 1536K FFT length: 51.798 ms.
Best time for 1792K FFT length: 63.482 ms.
Best time for 2048K FFT length: 70.768 ms.
Best time for 2560K FFT length: 93.152 ms.
Best time for 3072K FFT length: 110.999 ms.
Best time for 3584K FFT length: 134.020 ms.
Best time for 4096K FFT length: 150.764 ms.
Best time for 5120K FFT length: 189.191 ms.
Best time for 6144K FFT length: 238.677 ms.
Best time for 7168K FFT length: 288.895 ms.
Best time for 8192K FFT length: 317.715 ms.
Timing FFTs using 2 threads on 1 physical CPUs.
Best time for 768K FFT length: 23.380 ms.
Best time for 896K FFT length: 28.422 ms.
Best time for 1024K FFT length: 31.196 ms.
Best time for 1280K FFT length: 40.520 ms.
Best time for 1536K FFT length: 48.719 ms.
Best time for 1792K FFT length: 59.153 ms.
Best time for 2048K FFT length: 64.755 ms.
Best time for 2560K FFT length: 85.534 ms.
Best time for 3072K FFT length: 105.290 ms.
Best time for 3584K FFT length: 127.394 ms.
Best time for 4096K FFT length: 140.563 ms.
Best time for 5120K FFT length: 184.461 ms.
Best time for 6144K FFT length: 225.321 ms.
Best time for 7168K FFT length: 275.776 ms.
Best time for 8192K FFT length: 301.549 ms.
Best time for 58 bit trial factors: 8.966 ms.
Best time for 59 bit trial factors: 9.196 ms.
Best time for 60 bit trial factors: 9.116 ms.
Best time for 61 bit trial factors: 9.153 ms.
Best time for 62 bit trial factors: 12.603 ms.
Best time for 63 bit trial factors: 12.635 ms.
Best time for 64 bit trial factors: 14.812 ms.
Best time for 65 bit trial factors: 14.605 ms.
Best time for 66 bit trial factors: 14.794 ms.
Best time for 67 bit trial factors: 14.800 ms.

same settings but with prime95 v25.7

Jeff Gilchrist · 2008-10-26, 23:30

Processor: Q9550 @ 3.6 GHz (overclocked, FSB 425 MHz)
Motherboard: ASUS Maximus II Formula
OS: Vista 64-bit
Memory: 4GB DDR2-1066
mprime: 25.7 build 3 Prime95 Windows64

Code:

[Sun Oct 26 19:25:23 2008]
Intel(R) Core(TM)2 Quad  CPU   Q9550  @ 2.83GHz
CPU speed: 3612.62 MHz, 4 cores
CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2, SSE4
L1 cache size: 32 KB
L2 cache size: 6 MB
L1 cache line size: 64 bytes
L2 cache line size: 64 bytes
TLBS: 256
Prime95 64-bit version 25.7, RdtscTiming=1
Best time for 768K FFT length: 11.349 ms.
Best time for 896K FFT length: 13.704 ms.
Best time for 1024K FFT length: 15.643 ms.
Best time for 1280K FFT length: 19.539 ms.
Best time for 1536K FFT length: 24.027 ms.
Best time for 1792K FFT length: 28.624 ms.
Best time for 2048K FFT length: 31.802 ms.
Best time for 2560K FFT length: 41.749 ms.
Best time for 3072K FFT length: 51.379 ms.
Best time for 3584K FFT length: 61.101 ms.
Best time for 4096K FFT length: 68.241 ms.
Best time for 5120K FFT length: 87.185 ms.
Best time for 6144K FFT length: 105.502 ms.
Best time for 7168K FFT length: 127.791 ms.
Best time for 8192K FFT length: 139.663 ms.
Timing FFTs using 2 threads.
Best time for 768K FFT length: 5.999 ms.
Best time for 896K FFT length: 7.189 ms.
Best time for 1024K FFT length: 8.358 ms.
Best time for 1280K FFT length: 10.238 ms.
Best time for 1536K FFT length: 12.612 ms.
Best time for 1792K FFT length: 15.073 ms.
Best time for 2048K FFT length: 16.939 ms.
Best time for 2560K FFT length: 21.967 ms.
Best time for 3072K FFT length: 27.114 ms.
Best time for 3584K FFT length: 32.141 ms.
Best time for 4096K FFT length: 36.050 ms.
Best time for 5120K FFT length: 45.961 ms.
Best time for 6144K FFT length: 56.203 ms.
Best time for 7168K FFT length: 67.575 ms.
Best time for 8192K FFT length: 74.263 ms.
Timing FFTs using 3 threads.
Best time for 768K FFT length: 6.945 ms.
Best time for 896K FFT length: 7.851 ms.
Best time for 1024K FFT length: 11.722 ms.
Best time for 1280K FFT length: 8.816 ms.
Best time for 1536K FFT length: 10.691 ms.
Best time for 1792K FFT length: 12.695 ms.
Best time for 2048K FFT length: 14.382 ms.
Best time for 2560K FFT length: 18.672 ms.
Best time for 3072K FFT length: 23.025 ms.
Best time for 3584K FFT length: 27.082 ms.
Best time for 4096K FFT length: 30.635 ms.
Best time for 5120K FFT length: 37.543 ms.
Best time for 6144K FFT length: 45.222 ms.
Best time for 7168K FFT length: 54.311 ms.
Best time for 8192K FFT length: 60.726 ms.
Timing FFTs using 4 threads.
Best time for 768K FFT length: 6.236 ms.
Best time for 896K FFT length: 7.039 ms.
Best time for 1024K FFT length: 10.274 ms.
Best time for 1280K FFT length: 7.718 ms.
Best time for 1536K FFT length: 9.064 ms.
Best time for 1792K FFT length: 10.622 ms.
Best time for 2048K FFT length: 12.070 ms.
Best time for 2560K FFT length: 15.726 ms.
Best time for 3072K FFT length: 19.174 ms.
Best time for 3584K FFT length: 22.596 ms.
Best time for 4096K FFT length: 25.721 ms.
Best time for 5120K FFT length: 31.599 ms.
Best time for 6144K FFT length: 37.974 ms.
Best time for 7168K FFT length: 45.434 ms.
Best time for 8192K FFT length: 51.364 ms.
Best time for 58 bit trial factors: 2.358 ms.
Best time for 59 bit trial factors: 2.347 ms.
Best time for 60 bit trial factors: 2.687 ms.
Best time for 61 bit trial factors: 2.834 ms.
Best time for 62 bit trial factors: 3.233 ms.
Best time for 63 bit trial factors: 4.130 ms.
Best time for 64 bit trial factors: 4.477 ms.
Best time for 65 bit trial factors: 4.932 ms.
Best time for 66 bit trial factors: 4.905 ms.
Best time for 67 bit trial factors: 4.889 ms.

petrw1 · 2008-11-04, 22:56

Quote:

Originally Posted by fivemack

Get a 64-bit operating system; Vista or 64-bit XP. There's absolutely no point, particularly if you're doing maths and so 64-bit multiplications come in handy, in running a 32-bit OS on contemporary hardware.

I'm pretty much sold on the idea of 64 Bit Vista (I only shudder slightly as I type this).

If I do so is there any noticeable GIMPS benefit to having MORE THAN 4GB of RAM (DDR2-1066)?

Oh and does it really matter if I get Home / Premium / Business / Ultimate / etc versions?

cheesehead · 2008-11-04, 23:45

Quote:

Originally Posted by petrw1

Oh and does it really matter if I get Home / Premium / Business / Ultimate / etc versions?

Only Business and Ultimate users are allowed by Microsoft to "down"grade to XP Pro.

http://download.microsoft.com/downlo...rencesheet.pdf

http://www-307.ibm.com/pc/support/si...TA-DWNGRD.html

http://direct2dell.com/smallbusiness...d-of-life.aspx

http://www.mydigitallife.info/2008/0...-extra-charge/

http://www.engadget.com/2007/09/21/m...-downgrade-to/

petrw1 · 2008-11-05, 00:50

Quote:

Originally Posted by cheesehead

Only Business and Ultimate users are allowed by Microsoft to "down"grade to XP Pro.

What about from the aspect of GIMPS performance, throughput, etc?

Xyzzy · 2008-11-05, 04:07

Quote:

What about from the aspect of GIMPS performance, throughput, etc?

Vista Basic is available in 64-bit. It lacks some of the fancy "Aero" GUI effects so it may be faster. More expensive versions of Vista just add on features. You can upgrade up the chain if you want once the OS is installed.

We read somewhere that the network part of Vista Basic is less sophisticated than the more expensive versions but we can't find a link to back that up.

We have Vista Basic (64-bit) on a laptop, with the "Classic" interface, and it works very reliably.

We would prefer to run Linux but on our laptop, no matter how much we tweak it, we cannot get it to sleep or hibernate reliably. (And believe us, we have spent countless hours on this issue!)

It really hurts because everything else on the laptop works with Linux. And we're not talking about via restricted drivers either. Straight Debian works OOTB.

The darn thing just goes "double maverick" when told to sleep or hibernate.

2008-09-26, 02:29	#352
petrw1 1976 Toyota Corona years forever! "Wayne" Nov 2006 Saskatchewan, Canada 3×5×313 Posts	so....where does that leave me in GIMPS ... so I accept that I won't have access to 4GB until the day I upgrade to a 64 bit OS that handles it ... and so if I understand GIMPS correctly: a) This does not in anyway restrict or slow down LL or DC tests b) P1 Factoring is not resticted or affected c) I will not be able to do ECM with b1/b2 over about 3.2 GB Am I close? Did I miss anything significant re: GIMPS or any of the sub-projects? I plan to, and want to without restrictions, run Prime95 (and possibly some other related software) 24X7 on all 4 cores.

2008-10-12, 17:59	#361
db597 Jan 2003 7·29 Posts	Intel E5200 at 3.3GHz Just put together an Intel E5200 today. Running on 667MHz DDR2 (was salvage from an old PC that crashed). Overclocked to 3.3GHz right out of the box. Benchmarks are similar to what a much more expensive E8500 would produce at stock. Pentium(R) Dual-Core CPU E5200 @ 2.50GHz CPU speed: 3324.86 MHz CPU features: RDTSC, CMOV, Prefetch, MMX, SSE, SSE2 L1 cache size: 32 KB L2 cache size: 2048 KB L1 cache line size: 64 bytes L2 cache line size: 64 bytes Prime95 32-bit version 24.14, RdtscTiming=1 Best time for 512K FFT length: 8.089 ms. Best time for 640K FFT length: 10.925 ms. Best time for 768K FFT length: 13.537 ms. Best time for 896K FFT length: 15.994 ms. Best time for 1024K FFT length: 18.759 ms. Best time for 1280K FFT length: 22.569 ms. Best time for 1536K FFT length: 27.584 ms. Best time for 1792K FFT length: 32.777 ms. Best time for 2048K FFT length: 36.496 ms. Best time for 2560K FFT length: 48.080 ms. Best time for 3072K FFT length: 58.762 ms. Best time for 3584K FFT length: 69.802 ms. Best time for 4096K FFT length: 78.224 ms. Best time for 58 bit trial factors: 3.237 ms. Best time for 59 bit trial factors: 3.222 ms. Best time for 60 bit trial factors: 3.211 ms. Best time for 61 bit trial factors: 3.235 ms. Best time for 62 bit trial factors: 5.267 ms. Best time for 63 bit trial factors: 5.274 ms. Best time for 64 bit trial factors: 4.849 ms. Best time for 65 bit trial factors: 4.812 ms. Best time for 66 bit trial factors: 4.831 ms. Best time for 67 bit trial factors: 4.801 ms.

2008-10-23, 14:43	#366
T.Rex Feb 2004 France 2²·229 Posts	mprime on prototype Nehalem 2.4 GHz 8 cores Hi, I've got results of mprime on a (prototype) Nehalem 8 cores 2.4 GHz . I'll not provide detailed results since I do not know yet if it is confidential or not. I'll just focus on mprime scalability. (Note that there are some errors while allocating memory for some of the FFTs.) At 8 MB FFT: For 2 cores, the scalability is about 98.5% (1.97) . For 4 cores, the scalability is about 82.2% (3.29) . For 6 cores, the scalability is about 71.0% (4.26) . For 8 cores, the scalability is about 66.6% (5.33) . Not so bad. George, 1) Do you plan to work on a version of Prime95 that will fully take profit of the Nehalem processor ? 2) Are there some limitations within Prime95 about the number of cores ? Is it able to run on a machine with more than 8 cores ? T.

2008-10-23, 14:57	#367
T.Rex Feb 2004 France 2²·229 Posts	Glucas on Nehalem 2.4 GHz 8 cores Hi, Here are some complementary results, dealing with the scalability of Glucas (tests done using my "personnal" tricks about Glucas...). As you can see, the scalability is ... incredible !! Much better than what I saw on our Bull Itanium2 NovaScale machine, I think. But I need to provide a comparison of Glucas and mprime performance on the same FFT size for 1 core. This comparison is useful because Glucas probably does NOT fill the CPU caches as good as mprime does ! So that it is more scalable but not as powerful... Later. T. Exponent: 43112609 . For 2 cores, the scalability is about 99.4% (1.99) . For 3 cores, the scalability is about 98.7% (2.96) . For 4 cores, the scalability is about 98.5% (3.94) . For 5 cores, the scalability is about 95.5% (4.78) . For 6 cores, the scalability is about 98.0% (5.88) . For 7 cores, the scalability is about 92.5% (6.47) . For 8 cores, the scalability is about 93.6% (7.49) .

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2008-09-26, 10:08	#353
James Heinrich "James Heinrich" May 2004 ex-Northern Ontario 23·149 Posts	a) There is no significant speed difference in LL testing between 32- and 64-bit versions of Prime95 (see my benchmarks page, you can see a direct comparison between Q6600 @ 3.4GHz in 32-bit and 64-bit Prime95 v25.6). a2) Not mentioned in your list of question, but at the above link you'll notice that TF is noticably faster on 64-bit up to 2^63 (see this thread for all sorts of detailed numbers and pretty graphs comparing 32- and 64-bit Prime95 performance). b,c) P-1 (presumably ECM is similar) works better with more memory (works faster, so can spend more time processing to higher B1/B2, so has higher chance of finding factors). 32-bit Prime95 you'll be limited to <2GB. 64-bit should in theory not be limited, and if I recall correctly the 64-bit version of v24.x does work fine, but be aware that v25.6 x64 is buggy when >1800MB of RAM is allocated (e.g. this thread, posts 329-333). Prime95 will prevent you from assigning more than 90% of the installed physical memory to itself; I believe on 32-bit Prime95 that would be the lesser of 90% of (physical RAM or 2GB), so for systems with 2GB+ that would be 1843MB.

2008-09-26, 16:27	#354
henryzz Just call me Henry "David" Sep 2007 Cambridge (GMT/BST) 7·29² Posts	is it possible for an OC to be stable with anything u throw at it in win32 but to crash in win64