Hi, my memory suddenly running in single channel mode. My memory is HP 4x2 DDR3 in FM2A68. The system is read my memory in 8GB, but the usable is only 3,96GB. I have tried some method to fix, msconfg method, cleaning up ram slot, clean ram it self, re install windows, update bios and the problem is still exist. My mobo have two slot memory, A1 and B1, if i put ram into A1 slot only, the system is running, but if i put ram only in B1, the system is not booting. How to fix these problem?