Max multiplier still only 10?

After playing with my DFI NF680i for only a short period of time it ran my QX6700 at 3400Mhz prime stable for 8 hours @ 1.45vcore

At 3500Mhz overnight I woke up to see the PC was off, so either it reached its max temp of 90degrees (which I doubt... it's sits around 80 degrees all other times while priming at this voltage) or it crashed and didn't boot up.
CoreTemp log tells me it didnt' reach sky-high temps either, taking into account the 15degree difference between CoreTemp and SmartGuardian (BIOS). I think it crashed at about the 2.5hour mark which is a lot longer than I thought it would last tbh!

I'll push for 3550Mhz tonight and see if I can get it to crash sooner, so I can narrow down where I need to focus the tweaks.
I also need to lap my QX6700.

Cooling specs:

DtEk Fuzion,
PA 120.2
DDC+ /w Petras top