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Old 2021-09-09, 10:33   #1
Sep 2021

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Default Maximum core count support in latest Prime95

Is the maximum core count support for Prime95 24 ? If yes then how do we run it with CPUs like threadripper that has more than 24 cores?
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Old 2021-09-09, 10:38   #2
axn's Avatar
Jun 2003

5,179 Posts

From whatsnew.txt
New features in Version 28.5 of mprime

7) Maximum number of threads supported rasied from 64 to 512.
Even before this change, it was supporting 64 threads. So I guess it can handle TR.
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Old 2021-09-09, 11:31   #3
paulunderwood's Avatar
Sep 2002
Database er0rr

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Originally Posted by avinashkv94 View Post
Is the maximum core count support for Prime95 24 ? If yes then how do we run it with CPUs like threadripper that has more than 24 cores?
The 64 core TR comprises of 8 chiplets and so it is best to run 8 workers at the current wavefront of GIMPS. Forget using Hyper Threading -- only real cores count.

Last fiddled with by paulunderwood on 2021-09-09 at 12:04
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Old 2021-09-09, 15:26   #4
kriesel's Avatar
Mar 2017
US midwest

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Welcome to the forum. It's understandable you'd not be familiar with the following since you're new here.

Just out of curiosity, where did the idea of 24 cores as a maximum for prime95 / mprime come from?
Drkirkby has posted in various locations about running mprime on a dual-26-core system. Madpoo on dual-14 earlier.

Some of us have run mprime or prime95 on KNL Xeon Phi with 64 or 68 actual cores, and tested what level of HT might be beneficial versus fft length. And posted benchmark results.

There are whole threads about Xeon Phi. And posts in draft in the reference info.
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