I ran Memtest earlier. If I run Memtest with only one cpu core it will pass. If I enable all 12 logical cores for the test it will lock up. Now I know I need to test this memory one stick at a time now but to someone more experienced with Memtest does this sound like bad memory or a weak IMC? 5820k 4x8:32gigs Corsair Lpx. Motherboard is X99 Sabertooth. I ran Memtest from a bootable usb stick for reference. It was the Passmark version.