Did you tried msconfig > boot > advanced options . maximum memory Apply and restart.
First time when I install OS I had I think 15.9GB Usable but after that everything back on normal and now no more 15.9 usable.
When I work something arround motherboard socket everything must be easy and I don;t like nobody to distract me or to hurry me, special if someone call me to install him and than constantly ask something... That was most sensitive operation Installing Intel processors... I everything check twice. Long time I didn't do that... After 5-6 years of playing with hardware I start to install CPU in Intel socket. OK and AMD know to be inconvenient special when someone
didn't remove cooler 2-3 years. And I can say I never bend pins on socket or on AMD CPUs, never... But that happen usually advanced users who work that long time and then forgot to pay attention.... Socket is not sensitive at all as people want to present only you need to be human, not animal.