Possible to Swap Dual 1.25 Processors for Dual 1.42?

Question

I have to replace my processors and perhaps the logic board of my original Dual 1.25 Ghz MDD Mac.
Does anyone know if the [FW800] 1.42 Ghz processors are compatible with the 1.25 model that preceded it by 5 or so months? Additionally, would the logic board work within the MDD mac?
Thanks,
C
Dual 1.25 Ghz MDD Powermac G4   Mac OS X (10.4.8)  

Answer 1

Based on some net research, mostly on the xlr8yourmac site, I found that the swap has been done by several Mac users with dual 1.25 GHz MDD G4s. The mods were made over a year or more ago and there weren't any follow-up qualifiers, so they apparently were good upgrades.
So, if you have to replace the dual 1.25 MHz processors anyway, going to the dual 1.42 GHz processors is a workable swap. However, the upgraders noted that the performance gain was modest, so doing it for performance alone probably isn't cost justified.
The information I found did not include any mention of logic board swaps and did not specify whether or not the processor swap affected the ability to boot into OS 9. I don't think it is likely the boot encoding in locked into the processors based on personally upgrading several processors on old Macs over the years.
Good luck with your processor swap.
Carl B.