FBDIMMs are either 800 or 667MHz and either will work in 3,1 2008
They are all DDR2
How To Install and Remove Memory Mac Pro
Mac Pro 2009 - 2012
2x2GB FBDIMM DDR2 667MHz @ $32
Mac Pro 8GB Kit
Komputerbay 8GB (2x 4GB) DDR2 667MHz ECC FB-DIMM 240 PIN
Two weeks have past. Still getting kernel pani crashes, even if I :
- removed and replaced all OWC RAM sticks;
- removed Apple OEM RAM sticks;
- unplugged WACOM tablet;
- did all tests available;
Called Apple and they now think it might have something to do with the mother board. Preliminary suggestion by them is the possibility of motherboard issue if the issue persists with new OS and no user data brought back.
That would also mean not reinstalling 3rd party applications so how am I supposed to work I don't know...
A minimal Mac OS only with Apple software and ujpdates on a newly formatted drive is called troubleshoot testing, not to have a full working system but as a means to diagnose the cancer's source and possible remedies.
And clone that. Going from that to using Setup Assistant and/or Migration Assistant or TimeMachine later to get a working system but not to muddy the waters - even a new test user account.
The problem has been resolved.
As is often the case with hardware/software problems, we might never really know.
After replacing RAM from OWC with new matched units and removing the Apple RAM originally installed. I got another KP crash.
Then someone suggested I remove my Wacom Intuos 3 tablet. Something spotted on the last KP crash report. After removing the tablet, it seemed to solve the problem. After 24 hours, I reinstalled the Apple RAM. Still no KP crash. After a further 24 hours, I reinstalled the tablet, with a new driver, the latest available from Wacom.
It's been two days now. Working normally and smoothly.
How to explain? Anyway, it looks good.