RAM - how much do I really have working?

Amanensia

Amanensia

Amanensia

Associate
Joined
2 Jan 2008
Posts
27
Hi,

My desktop is now five years old (bought from OCUK!) and I was digging through my hardware to see what could maybe use an upgrade. Memory was my first thought as it does sometimes seem to struggle a bit. The key specs are:

Motherboard: Asus X99-S Intel X99 (Socket 2011) DDR4 ATX Motherboard
RAM: Corsair Vengeance 16GB (4x4GB) DDR4 PC4-21300C15 2666MHz Quad Channel Kit
OS: Windows 10 Home 64-bit

In CPU-Z, I can see all four RAM sticks, and 16GB is reported.
However in Windows System, it only shows 8GB.
Entering the BIOS, that also shows 8GB.

I haven't ever upgraded the BIOS.

How can I tell what's actually being used - and if it's 8GB, what can I do to fix this?
 
Task manager
Task-Manager-Memory.png


CPU-Z
CPU-Z1.png


CPU-Z SPD (slots 1-4 identical; slots 5-8 blank)
CPU-Z2.png
 
Hmm windows is definitely only seeing 8gb and 2 of your 8 slots occupied. So that's all programs will be able to use.

I've no experience with quad channel systems but looking at the board what RAM slots do you have the ram in? Might make a difference as you'll have primary slots etc.
 
The board has eight slots: A1, B1, C1, D1 and A2, B2, C2, D2.

The sticks are in A1, B1, C1 and D1. I've verified this by physical inspection.

I'm pretty sure the sticks in slots C1 and D1 are being used - these show up in another hardware profile application (Belarc Advisor.)
 
I've just downloaded the latest BIOS and will update that if people think it's a good idea. I've heard the odd nightmare story of boards being bricked by updates after extended periods of time... Need to dig out a USB drive to do that anyway I think.
 
In Windows there's an option to limit physical memory.

Run System Configuration (msconfig), go to the Boot tab, click Advanced Options, and look at the Maximum Memory box. Make sure it's unchecked.
 
Have you recently changed anything? I have heard cases where an overtightened heatsink/waterblock can cause RAM to no longer be detected as the pins in the socket end up not making perfect contact.
 
Thanks for the responses.

No system changes for a long while. I rather suspect the system might have only been working with 8GB from the outset...!

I’ve tried the maximum memory setting - it was unset. Just to be safe I checked it and then unchecked it again and rebooted - no change.

I’m now in the process of running MemTest86. Interestingly when this started up it reported 8GB, but the next page highlighted 4x4GB physical sticks. I’ll post some screen photos once it’s finished all its tests. It’s currently on test 2 of 4 which rather sounds like it can see all four sticks...
 
Memtest screenshot 1: shows four passes, all passed. I presume each pass refers to one memory module.

Memtest1.jpg



Memtest screenshot 2: shows 8GB total physical memory.

Memtest2.jpg



Memtest screenshot 3: shows four modules.

Memtest3.jpg



A link to the Corsair website page for this memory - it's clearly 4x4GB.
https://www.corsair.com/uk/en/Categ...Hz-C16-Memory-Kit---Red/p/CMK16GX4M4A2666C16R


So I am utterly confused. Memtest64 clearly shows four modules, but only reports 8GB total storage, as does CPU-Z. The BIOS and Belarc also report 8GB, but both of these report just two modules.
 
OK so I decided to pull the two identified modules out and swap them with the other two. That didn't work - wouldn't even boot.

Next I tried putting all four modules in A/B/C/D2 rather than A/B/C/D1. Didn't work. Wouldn't boot.

Now I've put all four modules back in the A/B/C/D1 slots, and whaddya know, now using 16GB. Perhaps one of the modules was poorly mounted - enough to be recognised as a present module, but not actually useable. Never mind. Working now, and I don't need to upgrade memory after all :)
 
Amanensia said:
OK so I decided to pull the two identified modules out and swap them with the other two. That didn't work - wouldn't even boot.

Next I tried putting all four modules in A/B/C/D2 rather than A/B/C/D1. Didn't work. Wouldn't boot.

Now I've put all four modules back in the A/B/C/D1 slots, and whaddya know, now using 16GB. Perhaps one of the modules was poorly mounted - enough to be recognised as a present module, but not actually useable. Never mind. Working now, and I don't need to upgrade memory after all :)
Click to expand...

Don't forget to load your XMP profile, it might just be because you were testing but from your CPU-z screenshots it looks like you were just running them at standard JDEC spec instead of your faster xmp profile.
 
Finners said:
Don't forget to load your XMP profile, it might just be because you were testing but from your CPU-z screenshots it looks like you were just running them at standard JDEC spec instead of your faster xmp profile.
Click to expand...
Thanks for reminding me, I did indeed forget to reload the XMP!
 
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