?I am running a Phenom II X6 1090T with 4gb G-Skill F3-16000CL9-2GBRH

Well I easily reached 4ghz with both the x4 and this x6 on the gigabyte
890gx mobo with noctua DH-14 aircooler, by simply changing the muliplier &
raising the core voltage, so yours should oc quite a bit. The first thing
I'd do is check for the latest system bios on the asus site. Then, since
your having such issues ocing at all, I'd first make a boot usb flashdrive
with memtest86 on it, and use that to test with before attempting to boot
into windows and risking harddisk corruption.

Also I suggest setting your memory to manual bios settings at whatever the
suggested timings are and verifying that the memory multiplier is not
overclocked, then start bumping the core multiplier & core voltage notch by
notch using memtest86 to test stability. I'm currently at 17x240=4080mhz
@1.5v, which you should be able to reach easily eventually.

rms