If, like me, you’re putting together a system based on the Gigabyte GA-P55M-UD2 motherboard with, say a Core i5 720 and some of the Gigabyte-approved G.Skill RAM, and you can’t get it through Memtest86+ at all, try the beta F4 BIOS. It adds a setting for vdroop handling that defaults to “Intel Spec” but allows you to change it to some more direct method…this resolved my bluescreens / memtest errors.