Hi to everyone, and thanks in advance for any assistance anyone cares to give! I have a rather odd memory issue which no one else seems to have experienced or is able to fathom (at least on dome of the other forums or techies I've asked). System is X99 Asus Deluxe 3.1 with a 5820K 32GB of Corsair 2666MHz 8GB X4 Ram ,780Ti OCZ 1000W Gold PSU & Two 850EVO in raid 0 The system works fine 90% of the time except when gaming when it falls over with BSOD which appear to be memory related, however the memory itself tests A OK and if there are two stick in then it's as stable as you could ever want a PC to be. Working through every combination possible with the sticks will not recreate the fault, it's only when there are all four sticks present that it falls over. Currently the motherboard is being RMA's and I will be replacing it with the X99 Deluxe II, but that is only based on suspicions because there are other issues with the board anyways. As I understand it the X99 memory controller is not on the motherboard, but the CPU the photos of which appear to show four distinct areas one for each channel. I am supposing that if the motherboard when returned does not cure the issue that the next place to look is the CPU ? I have not tried increasing voltages on the memory which might possibly be an issue, but seeing as it falls over at 2133 and at 2666 I don't think it's going to be that. Any ideas welcome !