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From: tankus@hsi.UUCP
Newsgroups: net.micro.pc
Subject: Re: Re: 80287 and the IBM AT
Message-ID: <418@hsi.UUCP>
Date: Mon, 8-Sep-86 07:42:48 EDT
Article-I.D.: hsi.418
Posted: Mon Sep  8 07:42:48 1986
Date-Received: Tue, 9-Sep-86 20:46:31 EDT
References: <3312@utcsri.UUCP> <253@psueea.UUCP>
Distribution: net
Organization: Health Systems Int., New Haven, CT.
Lines: 38

> In article <3312@utcsri.UUCP> henderso@utcsri.UUCP (Mark Henderson) writes:
> >I heard recently that the 80287 runs at a clock speed of only 5.3 MHz when
> >in an IBM AT and also that one can purchase a small board which fits into the
> >80287 socket on the AT, to drive it at 8 MHz (assuming of course one has an
> >80287-8). Where can one purchase such a board? Any information would be
> >appreciated. If you have them, please include prices.
> 
> Depending on what you are using, putting a 287 may not get you
> anywhere.  In fact, it may slow down your system!  
>  
> You may want to check the IBM special issue (10/85) of Byte, page 66 on.
> the benchmarks that they ran did not give the increase in proformence
> that you might expect.  In at least one case it slowed it down.
> 
> They used different clocks for both the 286 and 287;
> 286: 6 & 9 MHz
> 287: 0, 4, & 8 MHz
>  
> You might check byte for the speed up board for the 287, as I have seen
> them in byte.
> 
> greg waldref
> 
> ....tektronix!psu-cs!psueea!waldref

As I understand it, the faster your 286 goes the faster your 287 should go. 
Best bet would be to match the speed of your 286 with a 287 of comparable or
faster speed. Microway, Inc. in the Boston-area makes MANY 287-type speed up
products.


-- 

-- Ed.
    
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