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Old 2010-07-24, 23:45   #3
Rhyled's Avatar
May 2010

32×7 Posts
Arrow Core i7 suggestions

For what it's worth, I run an overclocked (3.7 GHz) Core i7 PC. I'll share what I learned along the way.

Hyperthreading on the i7 for Prime95 is a bad idea. Not only does the total throughput drop by 5%, but the core temperatures climb 5-10C. I simply turned off hyperthreading in BIOS. Whether or not you wish to do so may depend on the non-Prime95 work you do.

I hated going for weeks without a single result as several LL tests chugged along in parallel. I changed one worker to P-1 tests, which gives a 4-5 GHz-day payoff every 31 hours or so, and staggered the remaining 3 workers on LL duty to give me one result every 7-10 days instead of 3 results all on the same day. This staggering makes absolutely no difference to the overall project progress, but I get more consistent feedback that I'm actually contributing.

If you do allocate a worker to P-1, make sure you assign it a reasonable amount of memory. I think the default is 8 MB, but 1000+MB significantly boosts the chance of finding a factor. Most Core i7 systems have a decent amount of memory to match their processor.

On my secondary PC - an older Athlon X2, I run double-checks. Those LL-D checks take about 1/4 the time new LL checks take (with much higher exponents). I wasn't willing to wait 2.5 months for a result to appear.

Thank you for returning to Prime95. Whatever allocation you decide to make, we appreciate your contributions.

Last fiddled with by Rhyled on 2010-07-24 at 23:46
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