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From: hd@kappa.rice.edu (Hubert D.)
Newsgroups: comp.sys.ibm.pc
Subject: Re: 40 MHZ 286?
Summary: This is a best guess
Keywords: speed performance 286
Message-ID: <2002@kalliope.rice.edu>
Date: 14 Oct 88 15:07:33 GMT
References: <342@intek01.UUCP> <24728@bu-cs.BU.EDU> <3333@homxc.UUCP> <7761@bigtex.uucp> <670@hgcvax.uucp>
Sender: usenet@rice.edu
Reply-To: hd@kappa.rice.edu (Hubert D.)
Organization: Rice University, Houston
Lines: 22

I also read the column in PC mag.  My intuitive analysis is that
he is using the prefetch queue to get his speedup.  The article
points out that this modification only works on the Harris version
of the 286.  the Harris chip is a cmos version of the processor.  It
has the distinct advantage of being totally static.  The internal
registers are not being refreshed (like dynamic ram).

The use of the cmos 286 and a very clever external circuit allows
them to switch between 40Mhz (while executing instructions in the
prefetch queue) and 12Mhz (while doing memory I/O).  

The best short description we've come up with is "bursty" mode to
describe the clock switching processor. \

Note: the processor doesn't melt because it is given the chance to
cool off whenever the processor needs info from ram.

These are my own thoughts based upon the sketchy details presented
in the article.

Hubert Daugherty
hd@rice.edu