Windows – Why Task Manager is showing lesser RAM than installed?

memorytask-managerwindowswindows 10

I was surprised to open Task Manager on my PC, as the RAM it was showing was 8GB, because actual RAM I installed was 16GB. I instantly opened up my cabinet and put both my 8GB RAMs into different slots. Rebooted and opened up dxdiag to confirm I had 16GB RAM.

But Task Manager still showed 8GB RAM.

Task Manager showing less RAM than installed

On the other hand, the UEFI says I have only 8GB RAM available. Here are my motherboard details:

Manufacturer           Product     SerialNumber     Version
ASUSTeK COMPUTER INC.  M5A97 R2.0  141134705803134  Rev 1.xx

I've read this post: RAM usage % on Task Manager lower than actual RAM but I don't find anything relevant. Earlier, Task Manager used to show full 16GB RAM inside the left column.

Best Answer

I noticed there is a lot of hardware reserved RAM (a bit more than 8GB).
According to some quick research, there is incompatibility between your motherboard and some of the DIMMs.

According to the answer from this superuser question:

After much research I've found that the "system reserved" message is a generic message that windows uses to say you that some of your memory is locked by the BIOS. The problem is it can happen for a number of reasons, even a few that are software related, but it's usually hardware.

In your case I think it's a memory compatability problem with your new sticks. One thing that affects memory compatibility is it's density level. Which is how much memory is packed into each memory chip and can affect the hardware's ability to access it. Another related issue is if it's single or double sided, which is if the chips are on both sides of the stick or not.

Also, according to an answer from Tom's Hardware forum (slightly modified):

I don't see those XX sticks on the support list. I am putting my money that this is the issue.

I have had weird issues like that.

As a matter of fact I have proof that this is the error:

I have had a system that did this exact same issue of not recognizing the full 20GB of RAM. It was like only seeing 14 GiBs or something stupid.

I did sort of "resolve" the issue by swapping the slots. But my client experienced some very interesting issues that perplexed me. I created a post here for it:

My issue (posted below) can be categorized in the same way as your issue I am very positive of. Unsupported modules.

http://www.tomshardware.com/forum/id-1634727/motherboard-running-8gb-modules-4gb-supported.html

The solution: I ordered memory suggested for the mobo and my client has been clear of this issue since then when it was a constantly occurring. Now she can work as normal.

Another similar problem solved:

After removing the RAM and buying and installing two new 4GB sticks of RAM, my problem is solved!

Now I have less than 100mb hardware reserved.

After adding the old ram to the mix to give me 16gb, I am back to having 4gb hardware reserved, but now have 12gb dedicated.

So I think one of the old RAM modules must be faulty somehow.

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