In general, Intel's "OverDrive" processors (there were 486 models
as well as Pentium and later) couple a recent CPU with additional
circuitry (power regulation, for instance) to allow them to be used
in older motherboards that could not normally handle the newer CPU's
requirements.
  What you may be thinking of is that on some 486 designs, the
original CPU was not socketed, but soldered directly to the
motherboard and so could not be removed; these designs included (if
the makers followed Intel's recommendations!) a socket for an
OverDrive CPU, and the 486-era OverDrive CPUs included an extra pin
for that socket which instructed the motherboard to disable the
soldered-on CPU.  That's the only case I know of where you would
install an OverDrive without removing the original.

  (For What It's Worth:  It usually seemed like you could buy a new
motherboard and a *normal* current CPU for what Intel charged for an
OverDrive model, so if your RAM/video/etc were compatible, that was a
better upgrade path.)

Dave Gillett
A+, MCSE, CCNA


On 14 May 2001, at 19:01, Joel M. Blackman wrote:

> My recollection is that the overdrive is not a standalone
> processor, but exactly what it says, an overdrive for a Pentium
> processor.  I think those things boost the performance of Pentiums
> (not PII's or PIII's).  By itself it is not a processor, and I
> suspect the burning smell was his mobo frying, especially since his
> old CPU would no longer work.

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