I've disabled the "enable hardware-assisted visualization" option as @Eddy asked about it. And it seems to solve the problem, I've been running a virtual machine for 10 minutes without a crash.
Although a bit worried about all the warnings avast displays underneath that option

@Spec8472 cpu is a i7 920
EIST, XDBIT, VT and VT-D on
Windows 7 64 bit
Virtual machine is a centos 6.8 64 bit
No dumps cause i pressed the power off button quickly after a crash, all that beeping, fans spinning up and harddisk rattling scares me a bit.