No, this is not possible. All our X9Dxx boards are only validated for use with 2 cpu’s. this is because the new Intel architecture. When you only place 1 CPU in socket #1 The boards will start, but not be 100% fully functional. PCISome PCIe slots will not function. When paced in socket#2, the board won’t boor at all, because only socket#1 is connected to the chipset. The PCIe slot numbers that work/don’t work with 1 CPU may be different by mainboard model. Also it is possible, that on some boards lan ports or onboard controller does not function when using 1 CPU.