I run 24/7 @ 5.0MHz info as follows, if I run LL1 in bios from 1.48v - 1.54v overclock will fail.
What I'm saying is BSOD in windows & or bios not loading, reboot fails all the time.

If I run LL2 with 1.48v set in bios, when I get into windows it reads 1.50v & underload 1.52v but it's 100% stable.
LL2 works great for me, hope this helps...