Hi,
Just wanted to add my 0,02$ as i have a similar issue.
Ever since i updated to the f5 bios ( i thought it would get rid of the electrical noise , but it didnt, i had to disable c1e) my board wont recognize all 6 GB of ram.
I've got G-skill F3-12800CL9T-6GBNQ Ram (XMP turned on so they run at 1600MHZ)and i checked every single ram stick in every single slot on the board- it boots fine and its stable.
Now the funny thing.
If i boot my PC , go directly to the BIOS , and
change ANY setting that has to do with ram , turn XMP on or of, change a timinig, or just switch "performance boost" from standard to turbo ( or vice versa) and then save and exit , then suddenly , after the re-boot
all 6 GB are working fine and stable as a rock ( tested with memtest).
So its definitely a software/bios issue , any help would be appreciated ( maybe theres a bios setting or something that will help) as its no big issue but it is anoying My Rig:
Core i7 930
6GB Gskill ram
Nvidia GTX 480
1 TB Samsung F3
Sony optical drive
Corsair CMPSU-950TXEU