Motherboard or RAM

So here I am working on a large Photoshop image (160 x 250cm @200ppi) when I notice a bit of a slow down. I check my system and notice I only have 24gb RAM ( should be 32gb using 8 sticks ). I check all the ram in different sockets and run Memtest, all seem fine. Time to troubleshoot.

I am using an Asus p9x79 motherboard and have read this board is known to have issues by dropping out 8gb of Ram when 32gb has been installed, I have no idea how long this has been going on.

From a cold boot, the systems fluctuates between 24gb to 32gb. If I go into the bios ( up to date to the latest version ) while it sees 24gb and enable XMP, reboot, enter bios again and disable XMP, reboot I can get the system back to 32gb and all is good for the days session. Clearly something is not right. Any ideas what is going on?

Any advice is welcome.

Keep safe

hello farrellart,

How much RAM does Task Manager > Performance > Memory show? Please post a screenshot.

Are you using the latest BIOS as that could be a factor. If the BIOS only shows 24 GB, that's all I would expect Windows to show.

Hi,
More likely cpu dragging quad core.

Thanks everyone,

The RAM is on the QVL list = KHX1333C9D3UK2. @ThrashZone I am wondering what you mean by cpu dragging quad core?

This was my effort this morning to get the RAM from 24gb to 32gb.


Start up from cold boot.

After enabling XMP, reboot

After disabling XMP, reboot

After enabling XMP and disabling again, reboot

Bosh! finally full RAM as shown in Win10

A bit of a palaver, but, I got there in the end. Note: when only I only see 24gb in the Bios it is alway slots D1 and D2 that show up as abnormal ( all RAM shows up in CPU-Z ). If I reseat D1 and D2 RAM slots it reports back as normal and all is good again. The system is around 10 years old, and apart from this issue, it's very reliable as my High Res Photoshop Workstation. The CPU has never been OC'd and Bios is on the latest version.

Do I need to troubleshoot the CPU too?

OK, it's back again. Only 24gb ram showing up.

I have noticed that if I cold boot into BIOS straight away only 24gb is recognised, however, if I wait until the CPU temp rises to >30 degrees C and restart then I have all my 32gb to play with.

I think that's a bit odd, anyone experienced this before?

Best wishes

Try clear CMOS.

Grom0X said:

Try clear CMOS.

I have the manual but missed this, thanks for the heads up, it's worth a shot!

steve108 said:

Maybe one module is not installed correctly or there a temperature related hardware problem somewhere like an intermittent solder joint. I would reseat all or RAM modules unless you can tell from BIOS which one is not being detected initially and target that one - maybe swap it with one from a different slot.

Thanks, I will try that too.