I ran Memtest the other day and everything was normal. I have noticed I'm running slighly slower RAM then some people on here. 10600 - CAS 9-9-9-24. I assume that still good?

It's not great, but it's not going to affect FSX all that much. You could try raising your dram voltage to 1.65v, dropping your timings, and then stress testing it see if it's still stable. Sometimes you luck out with some cheap RAM that can OC quite well. Try 8-8-8-24 and if that's successful, try 7-8-7-24