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-   -   Dual CPU perfomance hit (https://www.mersenneforum.org/showthread.php?t=7)

Hades_au 2002-10-13 08:33

Re: Best mix for dual P4
 
[quote] Xyzzy:
Is Barney okay? :shock: :D[/quote]

Barney covers it perfectly :D Thanks

binarydigits 2002-10-14 10:33

[quote="xtreme2k"]If your computer, say it is a Pentium 90, took 1 complete year to run a LL test, submit the results and you will get 1 year credited to your account.

If the same computer, ran 20 factors and took 1 year in total. Your account will be credited 10% of that, that is 0.1 year is credited in your accounts total.

THis is MY understanding and may or may not be correct. That is why I want someone who actually knows and tell me whats going on.[/quote]

I do actually know and I did tell you, but for some reason you don't want to believe me.;)

Using your example: if you set the P90 to trial factoring for the second year then it WILL get credited about 0.7 years of TF by the end of that year. If you don't believe me then try it for yourself. As an example: I still have a 233Mhz Pentium Pro which used to run DCs and ran a consistent 80 P90-hrs/day. About a year ago I changed it to TF and it now runs at a steady 57 P90-hrs/day. I noticed a similar ratio on other types of machines, but not exactly the same (it's more like 60% on an athlon, IIRC). One glaring exception is my 475Mhz K6 which actually earns more hours/day factoring than it does running LL tests (LL=55 h/d; TF=87 h/d), but that's only because the FPU is so bad. As you can see, it ran LL tests slower than the P-pro but is faster than it at factoring. SSE2 optimization has probably had an effect on the ratio as well, since it speeds up LL testing so much. I've never done a comparison on those as I figured running TF on such a machine would surely be a waste of time.

smh 2002-10-14 16:26

Maybe the FP improvement of the Ppro was bigger then the integer?
What if you let a real p90 trail factor for a year? This should be closer to 1 then the ppro. I guess when you let a P4 factor you'll get a lot less then 0,6 * LL years

QuintLeo 2002-10-15 20:46

The Pentium Pro vs. the Pentium 166 made some major improvements across the board - but the single biggest improvement was a MUCH bigger cache amount.

Essentially, though Intel doesn't like to talk about it, the Pentium-II was a P-Pro core with some minor "tweeks" to work better with older code. A lot like they really need to do to the Itanic to get any reasonable acceptance for it.

Xyzzy 2002-10-16 04:27

One of the tweaks in the Pentium II was MMX... The Pentium Pro was the last Intel CPU to not have MMX...

That said, I'd rather have a Pentium Pro at 233MHz than a Pentium II at 233MHz... (Yeah, I'd have to overclock the Pro a bit!)

QuintLeo 2002-10-17 16:17

And for most usage, I'd rather have a K5 that did 233 Mhz than any Intel at that clock speed.

Would be horrible for Prime95/mprime, but for everything else it would rock....

Xyzzy 2002-10-17 20:00

I have a 200MHz 64-bit UltraSPARC CPU in my Ultra 1 that runs real well for it's MHz... It sucks on mlucas, but it excels in I/O operations...

BigRed 2002-10-22 00:06

Dual P4 results
 
[quote="outlnder"][b]BigRed[/b]

If you are so inclined, would you post your result times of the dual P4s running 2 LL tests. Let's see if RDRAM does minimize the bandwidth bottleneck.[/quote]

This box is a dual:
cpu family : 15
model : 2
model name : Intel(R) XEON(TM) CPU 2.20GHz
stepping : 4
cpu MHz : 2193.365
cache size : 512 KB

Mem: 1052626944

The box does get used for some non-Gimps work by the owner. It looks like all these were while the box was running LL tests on both processors.
Results.txt:
[Sat Mar 16 22:07:59 2002]
UID: cmarble, User: Chris Marble, cmarble@hmc
[Thu Mar 21 10:18:51 2002]
UID: cmarble/Jortner, M11331577 is not prime
[Tue Mar 26 19:01:26 2002]
UID: cmarble/Jortner, M11439511 is not prime
[Sun Mar 31 09:41:09 2002]
UID: cmarble/Jortner, M11956837 is not prime
[Mon Apr 8 19:39:01 2002]
UID: cmarble/Jortner, M13412753 is not prime
[Wed Apr 24 08:49:44 2002]
UID: cmarble/Jortner, M15304477 is not prime
[Sat May 4 15:15:58 2002]
UID: cmarble/Jortner, M15396919 is not prime
[Tue May 14 10:01:55 2002]
UID: cmarble/Jortner, M14525843 is not prime
[Tue May 21 06:57:45 2002]
UID: cmarble/Jortner, M14776589 is not prime
[Thu May 30 19:45:17 2002]
UID: cmarble/Jortner, M15675523 is not prime
[Tue Jun 11 20:42:49 2002]
UID: cmarble/Jortner, M15715457 is not prime
[Tue Jun 25 01:08:11 2002]
UID: cmarble/Jortner, M15783679 is not prime
[Sat Jul 6 12:46:54 2002]
UID: cmarble/Jortner, M15866687 is not prime
[Wed Jul 17 01:49:30 2002]
UID: cmarble/Jortner, M15974333 is not prime
[Fri Jul 26 23:00:24 2002]
UID: cmarble/Jortner, M16058719 is not prime
[Fri Aug 2 18:33:28 2002]
UID: cmarble/Jortner, M14169767 is not prime
[Tue Aug 13 02:14:22 2002]
UID: cmarble/Jortner, M16196387 is not prime
[Thu Aug 22 16:45:10 2002]
UID: cmarble/Jortner, M15607783 is not prime
[Sat Sep 7 02:55:40 2002]
UID: cmarble/Jortner, M16350739 is not prime

And resu0001.txt:
[Sat Mar 16 22:08:57 2002]
UID: cmarble, User: Chris Marble, cmarble@hmc
[Sat Mar 23 21:58:17 2002]
UID: cmarble/Jortner, M11721527 is not prime
[Thu Mar 28 22:02:15 2002]
UID: cmarble/Jortner, M11932229 is not prime
[Tue Apr 2 14:53:32 2002]
UID: cmarble/Jortner, M11983219 is not prime
[Sat Apr 20 11:55:20 2002]
UID: cmarble/Jortner, M15276089 is not prime
[Mon Apr 29 16:28:49 2002]
UID: cmarble/Jortner, M15352483 is not prime
[Sun May 12 06:20:45 2002]
UID: cmarble/Jortner, M15487861 is not prime
[Sun May 12 14:34:21 2002]
P-1 found a factor in stage #1, B1=195000
UID: cmarble/Jortner, M15555703 has a factor: 58689613794405579319231
[Wed May 22 10:04:51 2002]
UID: cmarble/Jortner, M15668431 is not prime
[Mon May 27 00:51:51 2002]
UID: cmarble/Jortner, M11950909 is not prime
[Sun Jun 2 15:23:23 2002]
UID: cmarble/Jortner, M13245691 is not prime
[Thu Jun 13 13:46:06 2002]
UID: cmarble/Jortner, M15021521 is not prime
[Mon Jun 24 09:51:47 2002]
UID: cmarble/Jortner, M15789497 is not prime
[Fri Jul 5 20:27:05 2002]
UID: cmarble/Jortner, M15904069 is not prime
[Tue Jul 16 16:20:39 2002]
UID: cmarble/Jortner, M15970807 is not prime
[Fri Jul 26 04:01:12 2002]
UID: cmarble/Jortner, M15390877 is not prime
[Fri Aug 2 14:00:12 2002]
UID: cmarble/Jortner, M14643457 is not prime
[Sun Aug 11 22:55:05 2002]
UID: cmarble/Jortner, M15430973 is not prime
[Thu Aug 22 00:10:50 2002]
UID: cmarble/Jortner, M16265621 is not prime
[Tue Sep 10 22:20:38 2002]
UID: cmarble/Jortner, M16345261 is not prime
[Tue Sep 24 14:02:17 2002]
UID: cmarble/Jortner, M16428437 is not prime
[Fri Oct 11 22:01:54 2002]
UID: cmarble/Jortner, M16630087 is not prime

Paulie 2002-11-12 21:51

[quote="garo"]Yes BigRed,
That is ideal. It is optimal from the project's point of view and also from the pov of optimizing your machines.[/quote]

Here's a question, for a dual P3 machine, one proc doing LL, the other doing factoring, would changing the max amount to factor to ^67 or higher make sense since the proc is dedicated to factoring? My machine completes a ^66 factor in the 21M range every couple of days.

I'm thinking of increasing it to ^67 to increase my chance of finding a factor (out of 10 TF's, I haven't found a factor).

garo 2002-11-12 22:33

Increasing it to 2^67 will increase your chances of finding a factor very minimally. You will have an additional 1.5% chance for twice as much processing power expended. . It is best to stick with the limits Prime95 adopts. You would be WAY better off doing more exponents to 2^66 than doing fewer till 2^67.

Assuming your starting bits are 59 your chances of finding a factor currently are about 1 in 9 or thereabouts. A bit more patience and you will be rewarded :D

lycorn 2002-11-13 20:41

[b]Paulie wrote:[/b]

I'm thinking of increasing it to ^67

That´s an interesting point. I assumed that the TF upper bound was, for a certain range of exponents, limited by the client, so for example in the 21M range we could only TF to 2^66. Regardless of being a good option or not (and I agree with [b]garo [/b]that it´s not) how *could* we change the TF upper bound?


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