The 'CPU Settings & Info' box in Prime95

Roy_Sirl · 2013-01-24, 18:30

I notice that for my i5-3570K, the CPU features listed are:
Prefetch, SSE, SSE2 and SSE4, but not AVX.
This is using Prime95 27.7 newly downloaded.

For similar assignments & FFT size, iteration times are slightly slower than for my i5-2500K's so I'm wondering if Prime95 is making use of the AVX instructions, or whether the slower performance is due to something else?
I was expecting the 3570K to at least equal the 2500K's.

All machines have 8Gb dual channel memory.

The CPU information box correctly lists the CPU, the CPU speed and cache sizes.

Any advice gratefully received,

Roy.

Roy_Sirl · 2013-01-24, 18:45

Well, I've just rebooted the m/c and AVX is now listed, and the m/c showing much better iteration times - down to .022 from .028, and the resuming primality test line says using AVX FFT.

Roy.

LaurV · 2013-01-25, 01:55

If you multi-thread the workers and/or use HT, please download 27.9 (the one you use had a small bug when multithreading workers).

tului · 2013-01-27, 15:24

Quote:

Originally Posted by LaurV

If you multi-thread the workers and/or use HT, please download 27.9 (the one you use had a small bug when multithreading workers).

Why hasn't 27.9 propagated to the web page as the latest version?

2013-01-24, 18:30	#1
Roy_Sirl Sep 2002 Cornwall, UK 2×5 Posts	The 'CPU Settings & Info' box in Prime95 I notice that for my i5-3570K, the CPU features listed are: Prefetch, SSE, SSE2 and SSE4, but not AVX. This is using Prime95 27.7 newly downloaded. For similar assignments & FFT size, iteration times are slightly slower than for my i5-2500K's so I'm wondering if Prime95 is making use of the AVX instructions, or whether the slower performance is due to something else? I was expecting the 3570K to at least equal the 2500K's. All machines have 8Gb dual channel memory. The CPU information box correctly lists the CPU, the CPU speed and cache sizes. Any advice gratefully received, Roy.

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2013-01-24, 18:45	#2
Roy_Sirl Sep 2002 Cornwall, UK 2×5 Posts	Well, I've just rebooted the m/c and AVX is now listed, and the m/c showing much better iteration times - down to .022 from .028, and the resuming primality test line says using AVX FFT. Roy.

2013-01-25, 01:55	#3
LaurV Romulan Interpreter "name field" Jun 2011 Thailand 41·251 Posts	If you multi-thread the workers and/or use HT, please download 27.9 (the one you use had a small bug when multithreading workers).