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From: thj@mtcchi.uucp (XT0221000-Tom Hjellming(ZG90210)0000)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: 8087 Coprocessor
Message-ID: <1990Jul16.152458.12373@mtcchi.uucp>
Date: 16 Jul 90 15:24:58 GMT
References: <1990Jul11.172043.525@bigsur.uucp> <673@mtune.ATT.COM>
Organization: Memorex Telex Corporation NSBG/STP
Lines: 41

klh@mtune.ATT.COM (Ken Hinds) writes:

>From article <1990Jul11.172043.525@bigsur.uucp>, by mussar@bcars53.uucp (G. Mussar):
>> In article <169@evtprp0b.UUCP> tea6219@evtprp0b (Terry E. Acker) writes:
>>>I have an XT with a V20 processor running at 8/4.77Mtz.  What speed
>>>coprocessor do I need.  If there are different speed 8087s, can I
>>>use a 4.77Mtz 8087 and set the system speed to 4.77?  What if I run
>>>the system at 8Mtz with a 4.77Mtz 8087?  Will it work?  Will it
>>>overheat?
>> 
>> If you plan on always running at 4.77 MHz, no problem. If you switch to 8 MHz,
>> chances are the system won't even boot/run. This is based on trying the same
>> experiment with a 4.77/10 MHz XT. YMVM. Even if if does boot/run, the 8087
>> (which normally runs pretty warm) will run VERY hot and this will decrease its
>> life significantly.

>Well, I have a dual speed 8088 micro processor in my Leading Edge 
>Model D and I have added an 8087 math coprocessore but, it is listed
>as an 8087-2  which implies dual speed... Sorry I don't recall the
>manufacturer but, I'm sure you could find it if you ask for it specifically.

I'm not sure if this is what you meant, but the '-2' on the 8087 does _not_
mean dual speed.  The 8087-2 is the 8MHz version of the 8087.

To the original poster:  I have an 8Mhz 8087 (the 8087-2) that I don't need
anymore (I've since sold the PC and upgraded to a 386).  Make me an offer...


Tom Hjellming
Software Consultant
Analysts International Corp. (AiC)
Schaumburg, IL
...!uunet!tellab5!mtcchi!thj

{ Usual dislaimers probably apply. }

-- 
Tom Hjellming
Software Consultant
Analysts International Corp. (AiC)
Schaumburg, IL