Don't do it! Better stick with the 1304 Bios.
I am no expert of BIOS, but what I know is, the 2012 bios did affect my OC performance, made it worse.
Before I flash to 2012, my system was stable with 1304 version. 4790k running 4.4ghz sync all cores at 1.18v core voltage, 4.4 cache with adaptive voltage and XMP 32gb 1600 ram. I am doing heavy duty 3D rendering, film editing with this computer so stability is the first thing I am considering and would compromising on speed if needed.
After the 2012 flash, my system goes unstable even under STOCK, not OC Bios settings, especially when I rendering with Houdini, it hangs randomly after a while. While using After effect and Premier decoding some footage, blue screen pops up, all these happened After I flashed to 2012 BIOS. The 2012 Bios is OK for gaming and anything that is not too extreme like huge 3d rendering or P95 for over 20 minutes.
Again, no expert here, maybe it is something else went wrong, but at least it happened after my 2012 BIOS flash. I am researching how to use Bios flashback to literally flash back my bios now
My specs are:
SABERTOOTH Z97 MARK 2 bios 1304 to 2012
Intel i7-4790K
Noctua NH D14
The cheap Gskill 4x8gb DDR3 1600Mhz ripjaws
840 Evo 250 ssd for windows 8.1, 840 Evo 120 ssd for windows 7 and a 2tb HDD
Cooler Master v750 psu
Quadro K4000 and GTX 760 none SLI
