Problem with p95, even though it uses ram to some degree in large and blend, that's only to some degree. P95 (small fft) is best for cpu heat loads, and thats about it.
For really putting ram through the works, use Asus RealBench or memtest86. Your OC can be totally stable 99% of the time, but it's that 1% you'll always seem to find when 2hrs deep in a game with a group doin a boss, and you haven't saved.