Question BIOS not recognizing all RAM

[Alucito]

I have an old rig.
Asus Maximus V Gene
Intel I7 3770
Ssd 256
Thermaltake tower cpu fan.
Corsair Vengeance 1600mhz 16gb (4x4gb)
Geforce Gtx 660ti
Ocz modxstream pro series 700 watts (Bought on 2012)
BIOS rog 1903
Windows 10

I have a pretty interesting issues in hand. My BIOS seem to be capped at 8GB. It doesn't matter what configuration I set the ram at, it only recognizes 8GB.
I tried a single different card on each slot to make sure all DIMMS and cards were working. They all post and show 4gb ram. So all ram cards and all dimm slots seems to be working.

In a nutshell, it seems like if I have 2 cards next to each other in the same channel, the MB only recognizes one channel.

Note: It always boots, on every configuration. it just does not recognize some of the expected ram numbers
I've tried every possible combination to figure this out:

A1 -> 4GB
A2 -> 4GB
B1 -> 4GB
B2 -> 4GB

A1 . A2 -> 4G
A1 . B1 -> 8G
A1 . B2 -> 8G
A2 . B2 -> 8G
A2 . B1 -> 8G
B1 . B2 -> 4G

Any other configuration after this is only 8G

A1 . A2 . B1 -> 8G
A1 . A2 . B2 -> 8G
A1 . B1 . B2 -> 8G
A2 . B1 . B2 -> 8G

A1 . A2 . B1 . B2 -> 8G

CPU-Z and BIOS show the DIMM slots filled with the correct RAM card information and placement.
Also, ran 6 passes of memtest86+ and it succeeded with no errors and showed all 4 dimms. One funny thing, it did show the memory to be 8GB (not sure if that's normal).
Windows task manager and resource monitor show 8GB as expected since the BIOS only show 8. Task manager says that slots 1 and 3 are empty.

• Ran Windows memory tool with no errors.
• Reseated my CPU and loosened the mounting screws a bit (since I read that could be causing issues).
• Flashed my BIOS and reset settings to default just in case. But I haven't done any overcloking. Even tried removing the MB battery for full reset.

I have to point out that I changed my cpu fan a while back and had to fix a bent pin in my MB. The computer is been working without issues. I do not remember checking my ram numbers back then. It just doesn't make sense to me that a bent pin would cap the ram but not have any other effect.

Any ideas? Suggestions on how to even tackle this issue?

 

[Lutfij]

Welcome to the forums, newcomer!

You forgot to mention the make and model of your PSU and it's age. When you state Windows 10, did you reinstall the OS after recreating your bootable UBS installer using Windows Media Creation tools?

 

[Alucito]

Welcome to the forums, newcomer!

You forgot to mention the make and model of your PSU and it's age. When you state Windows 10, did you reinstall the OS after recreating your bootable UBS installer using Windows Media Creation tools?

My bad, it's an ocz 700 watts. Updated the original post.
Everything was bought in 2012. The processor I bought used on 2017. But when I installed it I'm sure memory was all there.

Windows 10 is the OS I'm running. I installed it a while back. I think I did from scratch with a USB bootable.