Interesting. Do you think you could remove the MPC7447 CPU from a Peg2 G4 board and refit it with an MPC7447A?
That would guarantee 1.4 GHz operation (or higher).
I believe they are pin and voltage compatible.
I don't think so.
With higher frequencies ( 1.4 GHz and above ) I had memory read errors. From my opinion is northbridge MV64361 responsible for this, not CPU.
And also remove SMD and sold dip-switch is easy task, if I replace CPUs - there can be much bigger chance to disrupt something.
Even if I will succeed replace CPUs and northbridge have no errors with MPC7447A - the max frequency is 1.464 GHz - about 10% more than I have today. It is only small surplus with great risk.
AmigaOS: Pegasos II, Sam440ep-flex, Micro A1-C, AmigaOneX1000
MorphOS: Pegasos II, Powerbook G4, iMac G5, Powermac G5 Quad