I got SpecTek memory, which does 175MHz at 2.5/6/3/2 (CAS, precharge delay, RAS to CAS, RAS precharge)with default voltage. Anything above this setting will cause error in Memtest86. For CAS=2, even at 166MHz, it was no go...
The amzing thing is that a generic ram I got from FRY's a half year...