Can't figure out timings with SX58H7 board and GSkill 12800CL8TU

I just got the SX58H7 with a I7 920 and can't get the G.SKILL 6GB (3 x 2GB) F3-12800CL8TU-6GBPI to stay stable even at default settings. At default, it detects 6GB and runns at 1066MHz. With XMP, it detects only 4GB but runs at 1600MHz. When it does boot up, it's a crap shoot whether it's gonna stay on. Sometimes it crashs upon login, when opening picture files or running games(Farcry2/WoW) it will BSOD a nvlddmkm.dll error. I tried to adjust the settings manually (8-8-8-24) but it just boots in loops and I have to clear the CMOS to get back into BIOS. I RMA'd the memory but the new chips are still giving me problems. I figure I'm screwing something up somewhere. I've got the newest BIOS, running Windows 7 and have a nVidia GTX260 with the latest Win7 drivers.

you can download the motherboard manual here: http://image.shuttle.com/ResourceC [...] e_id=12733

Any help is greatly appreciated.

I tried the voltage when i did the timings manually.