Hi,

I have an old Area 51 mobo, I've been using it for a few years now with the following config:

i7 920 with TT 3.0 water cooler
3x4gb Hyperx Fury 1600mhz ram
GTX1050ti
Chieftec Smart 600w PSU
Win 7 64
A02 BIOS

Recently I made some upgrades:
- new cpu: Xeon X5687
- new bios ver.: A10
- new OS: Win10 Pro

After these upgrades, I noticed, that my BIOS and Windows can see only 8 gb of RAM instead of 12, but Aida and CPU Z can see all 12 gb. I checked all the RAM modules, all of it works in the1st and the 3rd slot, but none on it works in the 2nd slot, so there must be some sort of issue with the 2nd DIMM slot, not sure if it's a physical or a software error.

Any suggestion, what should I try?
Thanks in advance!