[SOLVED] Gigabyte 990XA-UD3 24GB RAM (20GB usable)

[findorgri]

I have a Gigabyte 990XA-UD3 mobo, with AMD FX-8320 and Corsair Vengeance 2x4GB 1866MHz. I added more RAM from the same series, only differences are size and frequency, everything else the same. The new RAM is 2x8GB 1600MHz.
The RAM is detected correctly by the BIOS and working @1600MHz as expected. However, in Windows 10 it says 24 GB (20 GB usable) and in the task manager it detects 4 modules but says that 4 GB are hardware reserved.
From my previous reading on this site, I was prepared for some possible issues since the ram modules didn't come from the same kit, even though they are the same(ish) model. I was hoping to get some guidance on what I can try to make Windows see all 24 gigs.

 

[DSzymborski]

I have a Gigabyte 990XA-UD3 mobo, with AMD FX-8320 and Corsair Vengeance 2x4GB 1866MHz. I added more RAM from the same series, only differences are size and frequency, everything else the same. The new RAM is 2x8GB 1600MHz.
The RAM is detected correctly by the BIOS and working @1600MHz as expected. However, in Windows 10 it says 24 GB (20 GB usable) and in the task manager it detects 4 modules but says that 4 GB are hardware reserved.
From my previous reading on this site, I was prepared for some possible issues since the ram modules didn't come from the same kit, even though they are the same(ish) model. I was hoping to get some guidance on what I can try to make Windows see all 24 gigs.

You can try to manually set timings and clock speed. Outside of that, there's not a whole lot to do. "Same series" is not same model. Even the same model doesn't always work out. Sticks are tested together for very specific reasons; semiconductor fabrication doesn't actually make "identical" parts.

 

[SamirD]

Did you follow the motherboard's instructions on how to bank the different modules? That can make a difference too.