Is the BIOS current?
How about a Web Speccy too?
Read how at https://www.piriform.com/docs/speccy/using-speccy/publishing-a-speccy-profile-to-the-web
Saw a bunch of similar problems but no solution worked for me. Maybe because they were not exactly alike.
Bought an additional 2x of 4gb corsair vengance and slotted into my Asus M5A97 R2.0.
The first pair works no probs. the second one is visible to both BIOS and Windows 8.1 but not usable.
The RAMs are fine - I switched them with the other ones and they work as 8gb just fine. It's only when all the 4 slots are taken, only the first two ones are used.
I cleared the CMOS, set the freq to 1600, vol to 1,5V, DRAM timing to 9-9-9-24 removed the max memory tick in the Win msconfig. No luck with any of that.
Any other ideas?
It feels like a motherboard/BIOS settings issue.