I have that same setup. I didn't know about the mobo BIOS update, I'll have to look into it.
The AMD 6300 works great at stock settings, but I can go absolutely no more than 400MHz over the clock, or everything shuts down on me. I wonder if the BIOS update will help.
Currently running stable at:
AMD FX 6300 at 3.9GHz (19.5 multiplier) with Cooler Master Hyper 212 EVO
EVGA GeForce GTX 750 Ti SC at only +50MHz GPU and +25MHz memory.
on MSI 970 Gaming