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From: c37189h@saha.hut.fi (Harri "Haba" Suomalainen)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Speeding up 286/386 (Was: Trying 25MHz?)
Message-ID: <1991Jan23.210741.4902@santra.uucp>
Date: 23 Jan 91 21:07:41 GMT
References: <1991Jan22.160249.5110@d.cs.okstate.edu>
Sender: news@santra.uucp (Cnews - USENET news system)
Reply-To: c37189h@saha.hut.fi (Harri "Haba" Suomalainen)
Organization: Helsinki University of Technology, FINLAND
Lines: 31

In article <1991Jan22.160249.5110@d.cs.okstate.edu> ong@d.cs.okstate.edu (ONG ENG TENG) writes:
>Well, a certain Mr. M (thank you) from Finland told me that his friend
>successfully sped his 16MHz 286 up to 25MHz with a small fan.

Hmm.. I suggested something like that for someone. Can't recall mentioning
a fan.. I was talking of 386SX.. Gotta be someone else...

>If you are braver, and wanna to go for higher speed, 
> .....

It sure is worth trying! I saved a lot of $$$ by getting a 16 MHz 387 to
my 25 MHz 386 machine. Now I'm thinking of trying to replace the xtal with
a 64 MHz to get a 32 MHz machine. You can never have too much power. :-)
I guess the 387/16 cannot take double frequency without a fan/heat sink.
Gonna try it anyway..

>Could anyone define hot on a chip (that requires heatsink)? 

I haven't the data on 286/386/387 enclosure nor on the power dissipation
of the chips. It should be easy to calculate. (Anyone got this data ?)

I had a temperature element taped on my 387 as I tried it. My chip was
heated to 50...55 degrees Celcius. I guess the silicon junction is
something like 100 C or maybe a bit higher. As these chips usually can
take something like 150..200 C, it should do no harm. (It has worked 
for 8 months now!) When I started testing I decided if enclosure heated
to 65 C or more I heat sinked it. Any expert around here ?

-hs
--
Harri Suomalainen         c37189h@saha.hut.fi         haba@otax.tky.hut.fi