I got exactly the same problem as you monkey dust.
Had multiplier at x10 FSB at 300, Gskill memory at 3-2-2-5, running sweet in Sli on 2x6800GT's at 415/1100.
Other system parts:
Raptor 74GB SATA (not raid)
Seagate 200GB SATA
Optorite DVD-Writer
Audigy 2 ZS
OCZ Powerstream 520w
Superpi 1m @ 34secs
Superpi 32m @ 29m 12secs
3dmark2001se @ 24904
3dmark03 @ 20901
3dmark05@ could not run had some issues with Sli
Unit was running then would not post, set-up speaker and got the memory failure post, tried all DIMMS after clearing BIOS/CMOS/Battery each time still got same problem.
How have you got on with yours? Was it the CPU? Or did you have a a 2nd dodgy MOBO?