> From [EMAIL PROTECTED] Thu Jan 14 13:25:19 1999
> To: Leu Enterprises Unlimited <[EMAIL PROTECTED]>
> cc: [EMAIL PROTECTED]
> Subject: Re: Mersenne: mprime for QA or performance?
>
>
>
> > Some things are known to happen; and I have observed them myself. First,
> > the amount of voltage required to work at a given speed decreases.
> > Secondly, the odds of the chip working at a higher speed increases.
>
> To me at least, the first part is obvious. As temperature goes up, so does
> resistance. The higher resistance requires a greater potential difference
> to send an adequeate(sp?) amount of current throught the processor.
> Without cooling, I would imagine the chip would eventually melt down. With
> cooling, I would imagine the voltage peaks out in some sort of gaussian
> curve. Which beings to mind, would the potential difference delta be a
> good measure of the quality of your cooling?
That's not been my experience. You can put on superb cooling, and crank
the voltage up all you want. It won't help a bad chip. You will only
fry the chip.
Don't forget that the CPU parts are spec'd at 2.5V; with a typical tolerance
of +/- 20 %. Running a C300A at 3.0+ V for long is likely to cause great
disappointment.
Furthermore, you are not guaranteed to run reliably at 504 MHz, if your
CPU handles 450 MHz @ 2.0 V. I have several such CPU's. And, FWIW, the
point of failure appears to be the FPU (no - not the L2 cache, like
most people assume).
> ...
>
> > It would be difficult to classify unexplored territory as "common knowledge".
> > Perhaps it's common knowledge to some; it's just not mentioned in the
> > more popular websites or forums.
>
> Almost everything that I have learned beyond 1st grade was by assuming
> that it was common knowledge. "If someone else understands it, I should be
> capable of understanding it too!"...
Ok - please explain to me members of the opposite sex. They certainly seem
to understand each other. :)
Seriously, I wouldn't classify the original subject as common knowledge
among overclockers at all. Or the latter subject, but let's not digress...
Back to my orginal point - is there truely no one on this list who
can knowledgeably state that the precision of mprime is suitable, or
not suitable, for these timing purposes? One area of concern is round-off
error. But there may be others as well.
TIA!
-dwight-
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