WHAT I DONT GET ABOUT THE WHOLE PRIME THING:
For one, it is completely unrealistic as there is ZERO chance you will ever be required to run your CPU full out for 12 hours straight. You might have a crash doing that after 5 hours (by just passing a random errata), but that doesn't mean that overclock would EVER rash in regular daily use.
In other words, you are rejecting an overclock that would work perfectly fine in a real-world scenario just because it crashed in a hypothetical scenario that would never actually happen? To me, this is foolish.
So, if your goal is to win some sort of overclocking contest, then run prime. If you are just looking for a fast desktop and gaming machine, who cares?
My rig at 180x21x3.8 might fail Prime, but it runs like hell all day real world and that's all I care about.
P.S., My B50 was real hinky at 3.8 when I went 200x19. However, it seems rock solid at 180x21 - who knows why? Anyway, I am benching pretty much equal to an i7 920 with this setup.
It is absolutely in your best interest to OC to a stable setting if you plan to use it every day, not just for a suicide run.