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From: stesin@elvisti.kiev.ua (Andrew V. Stesin)
Subject: PCI bus freq with CPU freq at (X * 40)Mhz?
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Date: Sun, 3 Mar 1996 20:03:50 GMT
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Sorry for ignorance, but what will be the frequency on a PC's PCI bus
when the CPU runs at main frequency of 40MHz (DX2/80, DX4/120 i.e.)?
I always thought that PCI will than run at 40MHz too.
But was told today that it will be only 20MHz?! Oh God.
How can I check this for sure, without running hated benchmarks,
but only by exploration of MB jumpers?
I was also told that having 40MHz will probably cause
an addition of extra wait states for cache and RAM access,
thus making a box considerably _slower_ for real work
than with 33MHz CPU main frequency, especially for UNIX-like OS
(FreeBSD in my case, but who cares). Any comments on this one?
And, in case both statements are true, why bother looking
at (X * 40)MHz 486 CPUs at all?
Thanks for your comments!
P.S. I don't own a PCI box, but just planning to buy one, choosing
the best bang-per-buck configuration now.
Was considering AMD 160MHz (glorified 486, called 5x86, he-he :)
chip, which has 40MHz main freq and 4x multiplier.
Now I'm seriously considering AMD 133 part (this one is 33MHz, 4x).
Guys have a very nice opinions on it.
--
With best regards -- Andrew Stesin.
+380 (44) 2760188 +380 (44) 2713457 +380 (44) 2713560
"You may delegate authority, but not responsibility."
Frank's Management Rule #1.