relax the memory timings a lot then see how far you can push the cpu. Once that is settled go back and start working on the memory timings.
I am not sure what you mean, I do not understand memory in overclocking. I have read about it but I still do not understand.
If I set my memory to a lower speed like 100mhz and I have my HT multiplier at 5x, my computer will still run unstable at ~240 (12x).