NetNews Usenet Archive 1992 #19/NN_1992_19.iso/spool/comp/sys/ibm/pc/hardware/23340

Text File | 1992-09-03 | 1.7 KB | 31 lines

Newsgroups: comp.sys.ibm.pc.hardware
Path: sparky!uunet!gumby!wupost!cs.utexas.edu!oakhill!tomd
From: [e-mail] (Tom Davidson)
Subject: Re: Ice-cap to tune a 486/33 to 50Mhz speed?
Message-ID: <[e-mail]>
Organization: Motorola Inc., Austin, Texas
References: <[e-mail]> <[e-mail]> <[e-mail]>
Date: Thu, 3 Sep 1992 16:22:47 GMT
Lines: 20

[e-mail] (Kyle Jones) writes:

>[e-mail] (Stephen Mintz exp 11/92~) writes:
> > Please do not do this, We at intel have rated that chip at 33 mhz, that means it
> > hasn't passed a quality test for 50mhz, and using it at that speed will cause
> > errors, and possible damage to the processor, if it were able to go at 50 mhz, we
> > would be selling it as one, and making the profit from it..:)

You should clarify that ...  The chip has been rated at 33 mhz at ambient temperature
with no heatsink. Under those conditions the die is probably at 100C at which
 it is rated at 33 mhz , at lower temperatures the chip will run faster.
For example , a chip I work with runs at 33MHz at 120C, 40Mhz at 100C 45 mhz at 25c
and almost 50 at 0c. However some chips hit a brick wall at certain speeds.
 The problem with speeding up the CPU is usually in the other chips on the mother
board, especially the Cache SRAMS 33Mhz is 30ns cycle, 50Mhz is 20ns. Your external
Cache SRAMS are usually faster than the CPU cycle, 10ns is a big difference.
If your mother board is rated for a 50Mhz processor, you may be in luck, the
ICE-cap should cool the 486 to nearly 0C case, the die will be at 20C probably
able to run at 40mhz (25 ns) if your lucky you may have a chip that runs at 50mhz.