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Thread: : Looking for definitive FSB / cpu clock / RAM speed ...explanation
face BY : Russell McMahon email (remove spam text)

1.    I am looking for a simple (getting old) but complete and correct
explanation of the relationships between Intel processor PCs of -

   CPU clock speed
   FSB speed.
   Necessary RAM speeds / ratings (DDR & DDR2 especially).
   Any other relevant clock speeds and timings (of which there can be

There is any amount of material available via Gargoyle and Wikipedia.
By selecting material to suit you can get any number of incompatible
Necessarily most are partially wrong or incomplete.

Can anyone either explain what needs to be known to come to grips with
the subject OR provide a suitably definitive reference?


2.    "Super Pi" as a benchmark  / Slow PC woes.

We've been running the "Super Pi" benchmark, producing pi to 1 million
places, as a means of comparing various PCs. As a consequence my
present desktop PC now runs 30% faster! :-) !!!! It's a P4 3 GHZ 1 MB
L2, 800 MHz FSB and I found that it was substantially slower than
comparable machines. A bit of digging showed that the RAM was being
clocked at 200 MHz and changing this showed why, as the machine got
very unstable. After various playings it appears (jury still out) that
the LGA775 cpu had had too little and inferior thermal grease used and
that apparently the cpu was throttling back to stay alive. No alarms
were being given and this theory seems feasible but a bit unlikely -
but it's now running Super Pi to 1 million places literally 30% faster
and with the RAM clock set to "auto" it's now not crashing. So far

My PC now calculates Pi to 1 million places in just over 51 seconds
which is slightly faster per cpu clock speed than some comparable PCs
we've tested. Best figure we have is 43 seconds for a purpose built
super fast gamer PC - suggesting that the less than 20% extra speed he
gets is hardly worth the effort. This is of course only one benchmark
out of zillions but was certainly useful as an indication that there
was something wrong with this PC.

Super Pi program here


Very useful processor and system information extractor.
Program name is not the original one but it makes it easier to
remember :-)



<001e01c77200$58216ae0$3e01a8c0@gaddiel> 7bit

See also: www.piclist.com/techref/timers.htm?key=clock
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Subject (change) : Looking for definitive FSB / cpu clock / RAM speed ...explanation

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