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From: louis@LCJones.aclib.siue.edu (Louis J. LaBash Jr.)
Newsgroups: comp.unix.bsd.freebsd.misc,alt.comp.periphs.mainboard.asus,comp.sys.ibm.pc.hardware.systems,comp.os.linux.hardware,comp.sys.intel
Subject: Re: PCI bus freq with CPU freq at (X * 40)Mhz?
Date: 5 Mar 1996 15:00:59 GMT
Organization: L.C. (Doc) Jones Foundation
Lines: 33
Message-ID: <slrn4jolrv.3na.louis@lcjones.aclib.siue.edu>
References: <DnpJqF.82n@info.elvisti.kiev.ua> <4hg8sa$1jn@heist.demon.co.uk> <Dns7BK.DBI@ritz.mordor.com>
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On Tue, 5 Mar 1996 06:28:32 GMT, Chris Mauritz <ritz@ritz.mordor.com> wrote:
|Iain Baird (iain@heist.demon.co.uk) wrote:
|: Andrew V. Stesin (stesin@elvisti.kiev.ua) wrote:
|: : 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.)?
[deleted]
|: Having said that, I have run PCI at 40MHz with a DX4-120, and it
|: worked (with AHA-2940 and S3-968). This made little or no difference
|: to kernel build times compared to 20MHz, although this is a crude
|: benchmark. Doing this could reduce the life expectancy of PCI
|: cards.
|
|Reduce the life expectancy? How? My experience has been that
|overclocked cpu's/cards either work or don't work from square
|one...they don't work and then fail. If you have different
|experience please share. I'd hate to think I'm risking expensive
|cpu's and #9 graphics cards...
Sure can, power-dissipation is proportional to speed, and power-
dissipation spells *heat*; that's why high-speed CPUs require heat-
sinks and fans. Look at some semiconductor data-sheets: you'll see
"ABSOLUTE MAXIMUM RATINGS", temperature, Power Dissipation, and
voltage. "Stresses above those listed under ABSOLUTE MAXIMUM
RATINGS my cause permanent device failure. Functionality at or
above these limits is not implied. Exposure to absolute maximum
ratings for extended periods may affect device reliability."
The above is an excerpt from an IC data-sheet, and is typical.
--
Louis-ljl-{LLaBash@eniac.ac.siue.edu | lou@minuet.siue.edu}