Amount of RAM does not add up

Tim Hutchinson · 12 Jun 2018 at 17:00

Hi All,
I have an Asus B350Prime mobo, with two 4GB sticks of DDR4 ram, but I am getting very mixed reports on the total ram.

BIOS says 4GB in slot A2, 4GB in slot B2. Total memory = 4GB
Windows (W10 pro) reports 8GB total, but only 3.94 usable
memtest only finds 4GB

Any body come across this before, or could offer any advice?

skyripper · 12 Jun 2018 at 17:03

Using 32-bit version of windows?
Using onboard Video rather than a gfx card?

MagicBoy · 12 Jun 2018 at 17:19

Sounds like you have 32-bit Windows installed...

Tim Hutchinson · 12 Jun 2018 at 17:21

Windows reports 64bit os and 64bit cpu (system properties screen). Could this be wrong?
If I boot to usb and run memtest it does not produce any errors but only finds 4gb ram. Surely booting to usb like this would eliminate a fault with the os?

Armageus · 12 Jun 2018 at 17:30

Depends if the usb memtest is also 32bit?

Threepwood · 12 Jun 2018 at 22:54

Update BIOS, run MEMTEST.

~>Dg<~ · 19 Jun 2018 at 10:26

also make sure you have the ram in the correct slots.some asus boards can be dicks for this.

Gimpymoo · 19 Jun 2018 at 13:37

Have you tried resetting BIOS to defaults?

Quartz · 19 Jun 2018 at 13:47

Tim Hutchinson said:
BIOS says 4GB in slot A2, 4GB in slot B2.

This is correct per page 1-12 of the manual. Are the DIMMs an exact match?

Phemo · 19 Jun 2018 at 14:56

Could also be worth reseating the CPU if all else fails. I've seen this sort of thing happen in the past, though usually with socket 1366 based i7s where the 3rd memory channel wasn't working correctly.

Edit: Ignore that actually, I missed that it was an AM4 board so since it isn't an LGA socket, the chance of that making any difference is minimal.