🚀 go-pugleaf

In <1992Dec15.101259.6401@sei.cmu.edu> griest@ajpo.sei.cmu.edu writes:

> I have been told that you can install a 16MHz '387DX in a coprocessor
> socket to work with a 33MHz '386DX and it will work ok (running Math
> instructions at the 16MHz rate).  I am not convinced.  Has anyone done
> this?  How does it work?  Are their any jumpers that must be set?
> 
>    Tom
> 

Tom:

To the best of my knowledge, you can't do it. Only the Intel 387 (and none
of the compatible chips from IIT,Cyrix,ULSI,C&T) supports running the CPU
and the coprocessor asynchronously. Not all motherboards supports this option
as there has to be a socket for a second oscillator and a jumper to select
either the CPU or altaernate oscillator for the coprocessor. However, Intel
docs state that the ratio of the respective frequencies has to be roughly
between 2:3 and 3:2, which tells me that a 33 MHz CPU wouldn't work with a
16 MHz copro. Sorry!

Norbert
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Norbert Juffa        email: S_JUFFA@IRAVCL.IRA.UKA.DE        Live and let live!

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