Re: [Prime] Which version for Pentium M?

Steven Noonan Tue, 15 Mar 2005 16:44:41 -0800

About your 598.03MHz oddity... I'd assume that it's using 'Enhanced SpeedStep', which is designed to be in an adaptive mode (only shifts the clock speed when it needs it, thus saving power). On my Pentium M machine, I have a program called PowerPanel, in which I can turn the CPU's AC setting from adaptive to performance... Is this possibly what's happening on your system? From what I've seen, I can get results all over the scale when doing a CPU clock frequency ID in adaptive mode.

And to anyone who knows the Pentium M architecture... I am wondering why the CPU supports SSE2, and yet when it's used, it slows Prime95 down. Is SSE2 in fact slower than SSE?

-Steven

[EMAIL PROTECTED] wrote:

++ 03-Mar-05 10:00 -0500 - George Woltman:

Also benchmark the Pentium M with version 24.6 setting CpuSupportsSSE2=0 in local.ini.


Yes, this helps a lot.  Iteration times with this option set are about
82-87% of what they are without it.

One other question... I see the following in my results.txt:

Intel(R) Pentium(R) M processor 1.70GHz
CPU speed: 598.03 MHz

IIRC, the CPU runs at 600MHz in "speedstep" mode, but I don't think
I'm in that mode based my timings and the fact that I'm running off of
AC power in the docking station.  Is there a definitive way to check
the CPU to see if it's in speedstep mode or not?

For those that are interested, here are my timings, HP nc6000, Pentium
M 1.70GHz, 512MB 333MHz DDR RAM, 2MB L2 Cache, WinXP SP2.

Without CpuSupportsSSE2=0:

Intel(R) Pentium(R) M processor 1.70GHz
CPU speed: 598.09 MHz
CPU features: RDTSC, CMOV, PREFETCH, MMX, SSE, SSE2
L1 cache size: 32 KB
L2 cache size: 2048 KB
L1 cache line size: 64 bytes
L2 cache line size: 64 bytes
TLBS: 128
Prime95 version 24.6, RdtscTiming=1
Best time for 512K FFT length: 45.088 ms.
Best time for 640K FFT length: 56.895 ms.
Best time for 768K FFT length: 69.502 ms.
Best time for 896K FFT length: 83.431 ms.
Best time for 1024K FFT length: 93.740 ms.
Best time for 1280K FFT length: 121.222 ms.
Best time for 1536K FFT length: 147.521 ms.
Best time for 1792K FFT length: 176.920 ms.
Best time for 2048K FFT length: 198.266 ms.

WITH CpuSupportsSSE2=0

Intel(R) Pentium(R) M processor 1.70GHz
CPU speed: 598.03 MHz
CPU features: RDTSC, CMOV, PREFETCH, MMX, SSE
L1 cache size: 32 KB
L2 cache size: 2048 KB
L1 cache line size: 64 bytes
L2 cache line size: 64 bytes
TLBS: 128
Prime95 version 24.6, RdtscTiming=1
Best time for 512K FFT length: 37.237 ms.
Best time for 640K FFT length: 49.499 ms.
Best time for 768K FFT length: 59.736 ms.
Best time for 896K FFT length: 72.852 ms.
Best time for 1024K FFT length: 80.819 ms.
Best time for 1280K FFT length: 104.554 ms.
Best time for 1536K FFT length: 129.104 ms.
Best time for 1792K FFT length: 156.253 ms.
Best time for 2048K FFT length: 172.844 ms.


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Re: [Prime] Which version for Pentium M?

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