Whoa, nice clocks on the x4 550
But you have to admit that if the 550 didn't unlock all 4 cores the x3 720 would've been superior. I tried unlocking mine but it wouldn't boot into windows with all cores no matter what, so i dropped the ideea.
For cooling i'm using a Mugen2 which is doing a nice job. Even better when i "upgrade" it with 2 scythe kaze@3000rpm (noise matters not to me, as long as it's cool).
just use the F5A ATM and tweak it slow
The board i have is the ddr3 version so i'm limited to f4g, but using f4a for now to see how much i can get out of all parts.
I will take your advice and experience into account and settle for 2400 nb clock and try to get best cpu speed and cas7 (maybe cas6 )
Seeing your results, the 550 looks more and more appealing to me