RAM Only Running at Half Capacity

EMFole · February 16

Hello everyone, first time long time.

I've recently discovered that my 32gb kit of Corsair Vengeance DDR4 3600mHz has been detecting in BIOS and Windows as 16gb, and seemingly at half the speed. When only using one stick, it also rates each one as 8gb, despite them being 16gb sticks. I'm not sure when this started happening, but I noticed since I just got in a new PSU in prep for an RX 7900xtx I just ordered (upgraded from 750w to 1000w). I'm a fairly experience builder, but not really an experienced troubleshooter, and this one has me stumped. I am sure that when I built this computer, it read at 32gb 3600mhz

I did notice a while ago that my PC was taking slightly longer to boot than normal, with BIOS time reaching over 15 seconds according to task manager. Previously this was at 0.0 seconds. I'm not sure if this is related, but it started happening far before I changed out the power supply and thought I would note that in case it's a sign of a dying component somewhere else.

Solutions I have tried:

Reseated both RAM sticks into their original slots and the other 4 slots on the MOBO
Tried 1 stick of RAM on its own in each slot. Did this with both sticks
Checked all PSU cables to make sure nothing was partially plugged or unplugged
Reset BIOS to default settings
Manually set voltage of RAM to 1.5v
Removed CMOS battery
Flashed BIOS

I think I've ruled out the sticks themselves being the problem, but I have not tried them in a different MOBO yet. I think I have an older Intel one lying around somewhere I could try, but need to check if its DDR4. I've exhausted all ideas I can think of and all ideas I can find when searching, so I created an account here to see if someone smarter than me has any idea. Any help would be greatly appreciated! Specs from CPU-Z are attached.

EMFole · February 16

EDIT: Task manager does show it running at 3600 mhz after manually setting it in BIOS, but still at only 16gb.

CaiPott · February 16

It's not half speed, It's just the difference between MHz and MT/s. Sellers market these RAM as they are 3600 MHz but actually they are 1800 MHz & 3600 MT/s. You can check the difference on Google.

Task Manager showing the speed as MHz is a faulty as well. They fixed it on last updates and changed to MT/s.

RAM shows as 16 GB is weird tho. Try to run on Live USB and see if it's becuz of your current Windows installation or not.

T487 · February 16

The part number (CMK16GX4M2D3600C18) is for the 16GB (2x8GB) model found here:

https://www.corsair.com/us/en/p/memory/cmk16gx4m2d3600c18/vengeancea-lpx-16gb-2-x-8gb-ddr4-dram-3600mhz-c18-memory-kit-black-cmk16gx4m2d3600c18

Are you quite sure that you didn't pick up the wrong one by accident? Do you still have the box, or invoice?

Alex Atkin UK · February 16

2 minutes ago, T487 said:

The part number (CMK16GX4M2D3600C18) is for the 16GB (2x8GB) model found here:

https://www.corsair.com/us/en/p/memory/cmk16gx4m2d3600c18/vengeancea-lpx-16gb-2-x-8gb-ddr4-dram-3600mhz-c18-memory-kit-black-cmk16gx4m2d3600c18

Are you quite sure that you didn't pick up the wrong one by accident? Do you still have the box, or invoice?

It is confusing how Corsair switched to setting the model number of sticks from a kit to the kit model, rather than the single-stick model. It used to be easy to know the size of the stick at a glance from the model number.

EMFole · February 16

2 hours ago, T487 said:

The part number (CMK16GX4M2D3600C18) is for the 16GB (2x8GB) model found here:

https://www.corsair.com/us/en/p/memory/cmk16gx4m2d3600c18/vengeancea-lpx-16gb-2-x-8gb-ddr4-dram-3600mhz-c18-memory-kit-black-cmk16gx4m2d3600c18

Are you quite sure that you didn't pick up the wrong one by accident? Do you still have the box, or invoice?

I don’t, I built this PC about 2 2 1/2 years ago, but you’re right I think I was just being stupid. Could’ve sworn I had 32gb originally, and when I read the sticker on one of the sticks it said 16gb. Now that I’m looking at it closer it says 16gb (2x8gb). Chalk this one up to user error! Thank you everyone for the replies!