Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!zaphod.mps.ohio-state.edu!ub!acsu.buffalo.edu
From: jones@acsu.buffalo.edu (terry a jones)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: 16mhz 386sx running at 20mhz
Message-ID: <32458@eerie.acsu.Buffalo.EDU>
Date: 9 Aug 90 21:14:35 GMT
References: <1990Aug7.230306.16069@agate.berkeley.edu> <1990Aug9.144532.677@athena.mit.edu> <12743@june.cs.washington.edu>
Sender: news@acsu.Buffalo.EDU
Organization: SUNY Buffalo
Lines: 37
Nntp-Posting-Host: lictor.acsu.buffalo.edu


>>If the CPU is rated for 16MHz, then do _not_ let the machine run at 20MHz! 
>>Take it back & yell at them for doing something that silly. You will wear 
>>down your CPU if you run it faster than its rated.
>
>Can you cite any reference to support this claim?  If not, can you give
>any explanation for why a CPU chip, or any other chip, should "wear
>out" if run at a higher-than-rated clock?
>
>My understanding of chip speeds, from listening to silicon designers
>and managers at Intel talk (I used to work there), is that there is no
>physical difference between chips that are rated at different speeds
>other than what is stamped on their case.  The faster parts have just
>passed the chip tests at a higher speed.
>
>I could be incorrect, of course, let me know.
>
>	Rob Bedichek

Rob is correct..  Manufacturers will sort CPU chips by speed as they pass 
testing at that speed.  I have had good luck running a number of CPUs at
elevated clock rates.  There is no justification to the theory that the
CPU chip will "wear out" running at an elevated clock rate.  I would be
concerned that increased temperature would cause the CPU to be more prone
to intermittent failure, since it is running beyond guaranteed speeds.
Personally, I'd get the box warm, set some diagnostics running, and let it
fly for a few days.  If there was no flakiness, keep it, being happy with
the deal I got...otherwise send it back an complain.

			Terry


-- 
Terry Jones   				{rutgers,uunet}!acsu.buffalo.edu!jones
SUNY at Buffalo ECE Dept.		  or: rutgers!ub!jones

You are in a maze of twisty little compiler features, all different.