Question BIOS shows 24 GB's, windows shows only 20GB

[RyanBlaze]

I recently bought 2 new Kingston HyperX Fury DDR4 memory sticks (8 GB, 2x4GB) which should give my X-99A motherboard a total of 24 GB (Other two DDR4's are both 8GB, also Kingston HyperX Fury).

Despite all 4 memory sticks showing up on both the BIOS and CPU-Z, Window's task manager only shows 20 GB (One 4GB DDR4 is missing).

All 4 of the memory sticks work fine on a MSI Z170A Gaming M5 motherboard, so they aren't dysfunctional, but I can't make 1 of the 2 4GB DDR4 on my Asus X99-A motherboard. Any thoughts?

Specs validation [CPU-Z]:
https://valid.x86.fr/ywk3ub

BIOS:

https://imgur.com/a/UGNIibj

View: https://imgur.com/gallery/UGNIibj

 

[Calvin7]

You can make any kind of memory combinations you want. Only thing is memory manufacturers won't guarantee such combinations to be compatible together.

 

[RyanBlaze]

You can make any kind of memory combinations you want. Only thing is memory manufacturers won't guarantee such combinations to be compatible together.

True, but its odd only one of them work on Windows, despite both being fully functional.