I have the same board ( Gigabyte 990FXA UD7) and the same corsiar ram, vengence 16gig kit. I bought the FX-8150 the day it came out, had to upgrade to the f6 bios to even get it to post, just recently updated to the F8a bios to increase support for the FX chip because it has some stability issues, namely in certain games such as Shogun2, get a CPU clock interrupt blue screen on startup everything, the bios fixed that. I also have the same issue with the vengence ram. Now with the F6 bios I was able to get it to run stable at 1600 mhz using the DRAM profiles. After upgrading to the F8a however the profile no longer will run @1600. It seems that even when using the profile it wont adjust the timings, so I think what needs to be done is to just set the timings and frequency manually. I wont have a chance to test on doing this for a few days, but when i do if I get it stable I will post an update.
When flashing the Bios VIA Qflash, it sets the Cmos back to optimized defaults.