8 gigabytes of RAM installed, windows only recognizes 4 gigabytes?

Jjbell150

Commendable
Jun 1, 2016
2
0
1,510
I have four 2GB sticks installed, from two batches, and until today that setup worked fine for me. Task Manager shows that there is 4GB installed, with 2 out of 4 slots used, which does not match reality.

Speccy and other diagnostic tools show 8GB, I've run Windows Memory Diagnostic which came back with zero errors and I've reseated the RAM and CPU heatsink.

I'm running Windows 10 Pro 64 bit, so the version is not an issue.

Only things I've changed recently are the case and keyboard.

Any ideas about what could be causing this?