I wouldn't bother OC'ing that at all.....it's valueRAM for the most part and it will probably just die under stress and extra voltage.....valueRAM isn't meant to OC at all.
Also with questions like these:
what one is better the 3-4-4-7 or 2-3-3-6 and what do u change in the bios?
You need to do some serious learning and research before you just decide you want OC your RAM.....RAM is probably the most difficult thing to OC due to timings, voltages, and simply getting it stable.
The timings are latencies.....faster time = better, so the lower number is faster latencies