Question PC is newly only seeing 4GB of 32GB installed RAM.

[ksilver117]

Hi all. My PC was built about six months ago and has mostly been working great. Today, it only sees 4GB out of the installed 32GB of DDR5 RAM. I've got two 16GB sticks (a Corsair Vengeance matched pair) and the BIOS is showing that I only have 2x 2GB sticks. I know for a fact the RAM has worked in the past, including as of this morning and nothing of note has happened in the last few hours. I've restarted several times, confirmed in CPU-Z and the BIOS that only 4GB is visible to the machine, and made sure my BIOS settings are default. Hoping somebody here has experienced something like this before.

ASUS X670-P PRIME
AMD Ryzen 7 7700X
Zotac NVIDIA GeForce RTX 3060
Corsair Vengeance 32GB (2 x 16GB) DDR5-5200 PC5-41600
Corsair RM850e 850 Watt

 

[Ralston18]

Power down, unplug, open the case.

Clean out dust and debris.

Verify by sight and feel that all connectors, cards, RAM, jumpers, and case connections are fully and firmly in place.

Could be that something has become loose due to heat related expansion/contraction and vibrations.

Ensure that the Vengence RAM modules are indeed fully and firmly seated in place.

 

[Misgar]

You're using almost same motherboard as the one in my latest system.

Are you using the two DIMM sockets recommended in the Asus user manual?

If you're running memory with XMP set at 5,200MHz, disable XMP and try booting at stock (JEDEC) frequency, probably 4,800MHz.
Check to see if 32GB visible in Windows with XMP disabled.

If system does not show 32GB:-
Power off system.
Switch off mains to PSU.
Remove one DIMM and see if PC will boot in single channel mode.
Check to see if Windows detects 16GB.

Remove the first DIMM.
Fit second DIMM.
Repeat above test.

You may find that one DIMM shows up as 16GB and the other DIMM doesn't, implying it's gone bad.

A more thorough test is to download and install MemTest86+ and create a bootable USB memory stick.

With one DIMM in the machine, boot up from USB and run a full cycle of MemTest86+. This will probably take an hour. Make a note of any errors.

Repeat the MemTest86+ check with the other DIMM fitted instead of the first DIMM.

You could then go on to test the DIMMs individually in the three other DIMM sockets.

With any luck, these tests will give a good indication of the health of your RAM, DIMM sockets and memory controller channels.

 

[ksilver117]

You're using almost same motherboard as the one in my latest system.

Are you using the two DIMM sockets recommended in the Asus user manual?

If you're running memory with XMP set at 5,200MHz, disable XMP and try booting at stock (JEDEC) frequency, probably 4,800MHz.
Check to see if 32GB visible in Windows with XMP disabled.

If system does not show 32GB:-
Power off system.
Switch off mains to PSU.
Remove one DIMM and see if PC will boot in single channel mode.
Check to see if Windows detects 16GB.

Remove the first DIMM.
Fit second DIMM.
Repeat above test.

You may find that one DIMM shows up as 16GB and the other DIMM doesn't, implying it's gone bad.

A more thorough test is to download and install MemTest86+ and create a bootable USB memory stick.

With one DIMM in the machine, boot up from USB and run a full cycle of MemTest86+. This will probably take an hour. Make a note of any errors.

Repeat the MemTest86+ check with the other DIMM fitted instead of the first DIMM.

You could then go on to test the DIMMs individually in the three other DIMM sockets.

With any luck, these tests will give a good indication of the health of your RAM, DIMM sockets and memory controller channels.

So I'll start by saying that I removed & reseated the RAM, and at least for now my PC is seeing all 32GB. I am using the DIMM sockets that Asus recommends, so thankfully that shouldn't have been the problem.

Hopefully reseating the RAM helped (I did try last night, but it didn't work. I'm assuming that was human error and I didn't seat it properly last night) but if I run into this issue again, I'll definitely take your advice here and see how it goes.

Thank you, friend!

 

[Misgar]

On unimportant old systems, I have been known to remove signs of tarnishing on the gold plated contacts of DDR2 and DDR3 DIMMs using a soft pencil eraser. This is probably a very bad idea from the ESD point of view, but cleaning stubborn deposits that cannot be shifted with Isopropyl alcohol sometimes effects a cure.

Good to hear your system is back up and running.