Can allocate more memory than my GPU has

[BooneyNoobington]

I have a Lenovo ideapad 720-15IKB with 16 GB of internal storage and an Radeon RX 560 with 4 GB of dedicated GDDR5 RAM.

I'm using amdgpu and opencl-mesa as drivers.

I installed vramfs on Manjaro via the AUR.

Stangely I can allocate more than 4GB of storage to a ramdisk. htop shows the elevated RAM usage even though it shouldn't show GPU RAM usage.

When I allocate less then 5GB to the ramdisk still elevated RAM usage is shown in htop. Is this expected behavior?

[Overv]

You're likely able to "allocate" more than 4 GB because the memory isn't committed by the driver until you start writing files to it. The memory usage shown in htop may be a result of memory mapping, but I'm not entirely sure.