OK folks, I upgraded mobo version, (680i, AR to A1). Then added an extra 2gb RAM, to make 4gb total (GEIL PC6400). Since then I can no longer overclock 
I can't overclock CPU from stock speed, (2.4ghz e6600). Before I could overclock to 3.2ghz easy, even had 3.6ghz running, but now I can't even get 2.5ghz. During stress, system freezes and I get C1 error (680i mobo), which is the memory controller.
RAM timings are slack (5,5,5,18,23) and everything afaik correct in bios.
vdimm 2.2, FSB 1.4, linked and synced.
It seems CPU is fine, perhaps a mobo or RAM issue, any clues?
I can't overclock CPU from stock speed, (2.4ghz e6600). Before I could overclock to 3.2ghz easy, even had 3.6ghz running, but now I can't even get 2.5ghz. During stress, system freezes and I get C1 error (680i mobo), which is the memory controller.
RAM timings are slack (5,5,5,18,23) and everything afaik correct in bios.
vdimm 2.2, FSB 1.4, linked and synced.
It seems CPU is fine, perhaps a mobo or RAM issue, any clues?