The C states are enabled yes - though under LinX it should be in C0 state the entire time.
I'm running the F8 bios, pretty sure the D0 microcode was introduced ~F5.
I have now tried 1.2V Vcore, VQPI 1.34V, VDIMM 1.65V, CL7, 1600MHz. No go, it bombs after the 2nd run of LinX (it was bombing...