*Update
-Updated my cards firmware - game still froze
-Updated my Realtek Audio HD driver via my motherboard website (ASRock) - Problem Solved!
Have been playing BF3 at 120hz with lightboost, Precision X, Synapse 2.0, both cards overclocked. No crashes so far and it would ALWAYS crash within 3-15 minutes in game.
Will this solution work for everyone? No I doubt it, but if you haven't tried it then give it a shot. I think the down clocking your cards solution is kind of BS to be honest.. why pay for an overclocked card that doesn't do what you paid for it to do?? If I was one of those people.. I'd return my card (unless only BF3 created that problem)..
just my 2 cents.
Hope the rest of you can sort out your issues, good luck!