+90% GPU's VRAM usage on Mojave

[SHiNE2K]

I have successfully installed Mojave 10.14.6 on my old PC using Clover v2.5k r5103 :

• Mainboard Gigabyte GA-B75M D3V
• CPU i5 3470
• RAM 8G RAM DDR3 1600MHz
• VGA MSI RX 470 OC 4GB
• SSD 128GB

Everything is fine but when i use iStats menu to monitor my system. I found that my GPU VRAM is alway above 90% while i only watch Youtube video on 1 tab Chrome like Image below.

Is this fine ? Here is my EFI (Link : https://www.dropbox.com/s/ocma1x1g1lp0za9/EFI.zip?dl=0) . Thanks