Hi Boogle,
I raised some of the voltages to this:
Memory Voltage: 2.2v
1.2V HT: 1.25v
NB Core Voltage: 1.5v
SB Core Voltage: 1.55v
CPU VTT Voltage: 1.25v
TCL: 5
TRCD: 5
TRP: 5
TRAS: 18
Command Per Clock: 2
TRC: 24
and it still did not work at 800MHz. You are defiantly right about the other chipsets as I put my four DIMM's in my Intel MB at work and they worked at 800MHz no problem. How comes our MB's often have a problem with 4 DIMM's at 800MHz when systems like this have 16 slots running at 667MHz.
http://www-03.ibm.com/systems/x/rack/x3850/specs.html
or
12 slots also at 667MHz
http://www-03.ibm.com/systems/x/rack/x3650/specs.html
Is 667MHz just a very stable speed?
lxtwin