A:Answer it currently has 16GB of ram(ADATA XPG 288 Pin DDR4 2400 (8 GB x2)) it has room for 2 additional sticks of RAM on top of the 2 included.
The different GB sizes of RAM currently for desktops is
16GB (Expensive) (putting 4 of these in would by 64 GB of RAM, WAYYYYYY More than ever needed)
8 GB (Somewhat Expensive, the included 2 in this computer would be $100 each for $200 total if you were to buy separate) (so 4 of them would be 32 GB, even this is WAYYY more than needed, 16 GB is for like ultra gaming)
4 GB (mid end what you see a lot of $500-700 PC builds using, still very good, but not future proof) (4 of them would be 16GB)
2GB and 1 GB also exist, but since this computer includes 2 8 GB Im assuming you dont care about them, sub 1GB is like windows XP era.
if you dont plan on removing the 2 8GB included, you can mix different sizes, so theoretically if you put in 2 16GB of ram you will have 48 GB of ram, I can not see why anyone would need this much ever)
Basically what Im saying is everything is upgradable. It's an ASUS motherboard so... yeah.
btw the motherboard in which you are putting the RAM into is ASUS H110 Plus.