Your PC is almost exactly like mine and I had the same issues for a long time.
First do not overclock, second update to the most recent drivers for GPU. If your game still crashes then next try to disable any Realtek devices like audio and network card, try one at a time. I replaced my NIC with an Intel gigabit NIC and a HT Omega audio card. After all that I still had very high CPU load on multiplayer so i switched to the Core i7 2700k which now is running 75% load and no more crashing, all that for BF3!