> I am fully aware of the Microchip specifications as
> indicated by my comment "not-recommended by
> Microchip" within my post. Rather than speculating on

Referring back to

http://home.clear.net.nz/pages/joecolquitt/0f84rc.html

you'll see that the frequency was measured up to 5.84MHz
(using 2k2 +22p). At this point the waveform has become
distorted and personally I wouldn't trust it. I can't say if the
limits suggested by Microchip are to guarantee the survival
of the F84A's RC internal circuitry or the perfomance of the
software. The F628 is specced to go to 8MHz with RC (which
you could probably exceed) if you need faster s/w, whilst the
original F84 on paper tops out at 4.7MHz

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