> From [EMAIL PROTECTED] Fri Jan 15 19:39:41 1999
> Hi,
Greetings! My sincerest thanks for clarifying this issue.
I have some comments and questions.
> I'd be surprised if burning in had an effect on iteration times.
I'm keeping an open mind here. Now that I know that mprime is
capable of accurately measuring this, and I suspect what the difference
is (see below), I'm going to do a quick observation on 6 CPU's which
I've just gotten in.
I too would be surprised - but the potential benefit is too great
to leave without some investigation.
> More likely, 100 iterations is not enough to get a truly accurate
> timing.
I haven't noticed much, if any variation, in reported times whether
it be with 100 samples, or 1000. Granted, I haven't done an in-depth
analysis of this; I've just noticed that the variation seems
minimal over a number of 100-unit samples across many time intervals.
> I don't know about Linux, but it has been noted before prime95
> iteration times can vary a few percent from day to day.
Indeed. I've come to the conclusion that what I'm seeing is clock
oscillator drift. This could explain what I've seen, if the CPU
wasn't warm enough to begin with. And it's consistent with the
above reports - assuming there are no background activity going on.
> mprime is great for QA. It generates heat (by FPU use) and tons of
> memory accesses. If there are any hardware problems there, they are likely
> to show up in an extended torture test.
Though my comments were more focused on the timing issue, on this I
heartily agree! It has been my experience as well.
Actually, I don't think people appreciate mprime enough. As I stated earlier,
using it has identified that a key point of failure on overclocking is
the FPU - and not the L2 cache (as many have thought).
Regarding heat - hmm. Here, you have to be careful. Generally this is
true. While mprime does take second place to memtest86, this is due
to the fact that mprime requires an O.S. (and hence you have other
distractions going on - like interrupts, etc.).
I've measured the difference in temp. to be around 2 C (this does depend
on your fansink, though).
But, there is one reported exception - win98. It's been reported (and
I haven't verified), that prime95 generates significantly less heat when
it's run on win98 than with other O.S.'s.
I have no idea why, and can only speculate.
> >and/or performance measurements,
>
> I'd guess its as good as but no better than any of hundreds
> of publicly available benchmarks.
A fair statement, as performance and the application should be considered
together.
What I was wondering specifically is how one can determine the Mflops
rating of a given system via mprime? I know how to measure it with various
benchmarks, and was curious how mprime could be used.
Pardon me if this is a FAQ; I haven't seen this described anywhere.
If someone could either point me to a reference, or give an explanation,
I would be greatly appreciative. Thanks in advance!
Best regards,
-dwight-
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