I could have been lucky that time too, I haven't tried to accomplish that again. I am running 2.5-3-3-8 though at DDR540, so I know this memory is capable of a lot.
If I were you, I'd try to just up the voltage, maybe to 3.0 or 3.2 and then turn your divider to 1:1, to *try* for DDR520. I might tri 2.5-3-3-8 as well.. and if it's not stable, I would blame your CPU. The new Venice chips overclock very well apparently.
Intel Core i7-3960X, GIGABYTE G1.Assassin 2, Kingston 16GB DDR3-2133, NVIDIA GeForce GTX 770 2GB
Kingston HyperX 3K 240GB SSD (OS, Apps), WD VR 1TB (Games), Corsair 1000HX, Corsair H70 Cooler
Corsair 800D, Dell 2408WFP 24", ASUS Xonar Essence STX, Gentoo (KDE 4.11. 3.12 Kernel)
"Take care to get what you like, or you will be forced to like what you get!" - H.P. Baxxter
<Toad772> I don't always drink alcohol, but when I do, I take it too far.