Looking for advice for a new PC....

[petrw1]

http://www.mersenne.org/bench.htm

Strictly based on the statistics on the above link each core could theoretically finish 42,000,000 in 30 days. IF it can run 24 hours a day with nothing much else taking CPU time.

However, based on previous posts in this forum and other related hardware/benchmark forums you will NOT get 100% throughput on each core if all 4 are running primenet.

[Housemouse]

How much would performance increase with a Q9450 and DDR3 memory?
Any idea in cost increase?

[James Heinrich]

Originally Posted by petrw1

However, based on previous posts in this forum and other related hardware/benchmark forums you will NOT get 100% throughput on each core if all 4 are running primenet.

For a Core2Quad with DDR2-800 you can expect an overall throughput with 4 cores of somewhere around 2.8x throughput of a single core. Based on some rough benchmarks I took yesterday, a Q9x50 series with fast DDR3 could be ~20% faster with 3 or 4 threads than a Q6600, so you should get at least 3 exponents processed per month, maybe a little more.

[Batalov]

Originally Posted by James Heinrich

For a Core2Quad with DDR2-800 you can expect an overall throughput with 4 cores of somewhere around 2.8x throughput of a single core.

Timed my Q6600 (@3200MHz) with DDR2-1066 (set FSB multiplier to 3:2):
For the popular 2048M FFT range (under 39.5M) range for a point of reference -
1 LL thread - 0.036s/iter
2 LL threads scale to 1.95x of a single core (0.037s/iter if you get the right pair of cores)
3 LL threads scale to 2.66x of a single core (0.042s/iter on a pair and 0.037s/iter on a one = 0.0405s/iter harmonic mean)
4 LL threads scale to 3.16x of a single core (0.0455s/iter)

The dual quad core at work scales much worse: all 8 threads (8 LLs) produce less work than 7 LLs. Sad, but true. So I run 7 LLs. (but this, combined, is still better than 6, 5, ..., 1) You have to use harmonic means of iteration timings reported in threads (obviously).

DDR2-1066 don't break the bank. Do DDR3 if you are rich.

[rx7350]

Please post your detailed system components list. It would be helpful if you would also post your overclocking settings in BIOS.

I'm interested in adding to my P95 farm, and the iteration times when running four LL tests looks quite good.

[Batalov]

Originally Posted by rx7350

Please post your detailed system components list. It would be helpful if you would also post your overclocking settings in BIOS.

I'm interested in adding to my P95 farm, and the iteration times when running four LL tests looks quite good.

Sure, too easy (as the Australians say) - http://valid.x86-secret.com/show_oc.php?id=339536

I believed in these principles -
1) weird multiplers (like 8:5 or 5:3) are not really working for memory, and
2) "thou shall not touch your memory's frequency" (the vendor OC'd it for you already! Especially if their name is Corsair)
=> so I had only two or three FSB frequencies to test.
266 x 4.000 = 1066MHz (original) 266 x 9 = 2400MHz (CPU)
320 x 3.333 = 1066MHz
333 x 3.200 = 1066MHz
355 x 3.000 = 1065Mhz

I liked the last one the best. The above timings are from this configuration.
In BIOS you need to know the Ctrl-F1 combination (it's not secret, it's in TFM) - and see the attached snapshot.

P.S. Memory shows in BIOS as DDR2-800 but it is sold by Corsair as XMS-1066
The parts list (built in December) -
http://www.newegg.com/Product/Produc...82E16819115017
http://www.newegg.com/Product/Produc...82E16813128059
http://www.newegg.com/Product/Produc...82E16811129021
http://www.newegg.com/Product/Produc...82E16817153039
http://www.newegg.com/Product/Produc...82E16820145043 and an HD and a video card

Added in March after getting addicted to GIMPS -
http://www.newegg.com/product/produc...82E16835154001 (very important, without it I had Tj=70C+ under the 4 LLs @2400MHz; now I have 60C under the 4 LLs @3200MHz) there are other good coolers too. But this one is the king.

P.P.S. And now is not December - it's time to buy Q9450 (or Q9300 at least) instead of Q6600.
Maybe there's a DDR2-1111 or 1200 choice already, as well. Up a notch everything, of course.

[science_man_88]

what would be really cool is if prime95 let you use readyboost as far as I know you can't if I could I'd be 5 times as fast lol.