Evening all!

Not posted for a long while but nice to see the forum still going strong.

I have a problem with my RAM at the mo. It started few months back where I was getting random BSODs and the pc randomly crashing on startup and shut down etc

So after some investigation I have managed to narrow the problem down the RAM.

Quick spec - MOBO is RIVBE
Ram is Hyper X beast 32gb 2133

The issue is that only 2 stick of RAM are showing in the BIOS. The other dimms are showing as N/A in BIOS. I have tried swapping them around, re seating, selecting XMP profiles etc and all to no avail.
The last time the system was running ok the RAM was running at 2400. When the issues started I then lowered it down to 2133 and everything worked ok. But then the BSODs started again and after checking the RAM in the BIOS that's when I noticed only 2 sticks of RAM are registering. If I click on the DIMM tab in the BIOS it shows that there is RAM in there but is showing as N/A

The DIMMs showing as N/A are slots D1 and C1
the DIMMs that are 'ok' are A1 and B1

I have also tried each ram slot on their own in slot D1 (as per the user guide if using 1 stick) doing this I manage to get the RAM to show up in the D1 slot in BIOS - but it will only post and boot at 1333?

So is this looking like a RAM issue or Mobo issue?

any help much appreciated!