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-   -   p4 with ht question (https://www.mersenneforum.org/showthread.php?t=3508)

crash893 2005-01-04 20:17

p4 with ht question
 
i have a 3.2 mhz with hyper threading witch shows 2 cpus

is it faster to do two instances of prime or should i just let it run 1

moo 2005-01-04 22:13

you got to do the math....
well first run one instance of prime 95 doing what ever your planuing on doing set it to 10000 illiterations next wait and get time for those illiterations next what you need to do is start up a second copy and get the times for the first copy and second copy ok now heres what you do lets say when you ran one copy you get 10000 illiterations in 250 seconds now when u started second copy it was 350 second now devide 250 by 350 now what happens is you are dooing 2 times the work and when you did the devision you got it was running at 71 precent witch means yes these are made up times but doing 2 does do more work but it takes a little longer for each to do said work....

Uncwilly 2005-01-04 23:07

The average user would want to do either a single instance or do one that [B]only[/B] does L-L testing and one that [B]only[/B] does Trial Factoring.

dave_0273 2005-01-05 05:12

I did all the timings on my p4 2.4ghz (with hyperthreading) and basically came to the conclusion that it was easier just to run the one instance. There is a slight speed gain overall by having one on LL testing and one on factoring however at the same time, it (almost) doubles the time for the LL test and the factoring assignment to finish. I don't know what you are like, but I like to see progress and having the already long LL test taking twice as long now just didn't seem like an option. So I decided just to run the one instance.

Maybeso 2005-01-17 00:51

I came to the same conclusion as you, except it bothered me that my account report had a zero in the 'Exponents w/Factor' column. So I set up the factoring thread to run for 8 hours a day while I'm at work. I only 'lose' one L-L day every 6 days, and I'm already closing in on the top 500 for factoring. :showoff:


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