Question B450 - Windows Reads 32GB Installed, Only 16GB is useable

Apr 1, 2020
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I have a Ryzen 7 1700, currently waiting for my Ryzen 7 3800X to be delivered as I type this. I decided to purchase an additional 16 gigabytes of RAM and I ended up getting Corsair, the same brand my friend uses in his B450. The serial is CMK16GX4m2B3200C16. The problem is, windows reads it and so does my BIOS, but it says only 16 gigabytes is useable. The other two ram sticks are G.Skill 3000Mhz, a different brand and frequency than my Corsair Vengance LPX 3200Mhz. I'm not trying to OC my RAM to 3200, I'm fine with it at 3000Mhz, but I just want the full 32GB, instead of only 16.

System: https://prnt.sc/rr4aa0

Although it's not listed on the QVL, I've read that many people use the exact same RAM on the motherboard, the processor they use, however, is a bit more updated such as the 3800X. Is this a problem I need to fix now or wait until my 3800X comes in a few hours? If so, how do I fix it?
 

kanewolf

Titan
Moderator
I have a Ryzen 7 1700, currently waiting for my Ryzen 7 3800X to be delivered as I type this. I decided to purchase an additional 16 gigabytes of RAM and I ended up getting Corsair, the same brand my friend uses in his B450. The serial is CMK16GX4m2B3200C16. The problem is, windows reads it and so does my BIOS, but it says only 16 gigabytes is useable. The other two ram sticks are G.Skill 3000Mhz, a different brand and frequency than my Corsair Vengance LPX 3200Mhz. I'm not trying to OC my RAM to 3200, I'm fine with it at 3000Mhz, but I just want the full 32GB, instead of only 16.

System: https://prnt.sc/rr4aa0

Although it's not listed on the QVL, I've read that many people use the exact same RAM on the motherboard, the processor they use, however, is a bit more updated such as the 3800X. Is this a problem I need to fix now or wait until my 3800X comes in a few hours? If so, how do I fix it?
Mix and match RAM is a gamble. See if you can get 32GB stable at 2133. Ryzen, especially first gen Ryzen were notorious for not liking 4 DIMMs at any speed but default (2133).
If you can't then you may have to live with 16GB. Or buy a matched set of two 16GB DIMMs if you want 32GB.
Remember to do the necessary BIOS updates before swapping to the 3800X.
 

MadsModsat

Commendable
Although some people have luck with the RAM despite not being on the QVL, you are making things worse by mixing RAM

Only RAM purchased as a matched kit, with the total amount of memory and number of modules you want, is guaranteed to work together.

Sometimes mixing RAM causes no problems, other times it causes instability and other problems, and sometimes the PC simply won't boot
 
Apr 1, 2020
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I ended up fixing this actually. I played around with the slots. I put my 3200Mhz in the recommended slots instead of the 3000Mhz there, then I set my DRAM speed to 3000Mhz, works perfectly now.
 

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