When does Unified Memory Access (UMA) grow with demand?

My computer does not scale the UMA when it is maxed out. My laptop has an integrated GPU (iGPU), 32 GB of RAM, and it makes use of UMA. Its UEFI firmware has the following possibilities to configure the UMA: - auto (default, used during test) - 512 MB - 1 GB - 2 GB - 4 GB - 8 GB - 16 GB I start a game (via steam + proton) and it runs poorly. I monitor the system via nvtop, and see the GPU is maxed out, both on VRAM and 100% load. Interestingly, the VRAM is indicated to be 512 MB. I had hoped it would automatically scale with demand, given that is the intended use with UMA. After manually setting the UMA to 8 GB VRAM, the game performs much better and uses 5 GB. I see this as a bug or a missing feature. Could it be due to the motherboard firmware? Do I have to configure Wayland in a certain way? Is it up to the program (proton/the game) to demand for UMA scaling? Do I need to activate a kernel module/set a kernel argument? **System info** Distro: NixOS 24.11 (Vicuna) Kernel: 6.6.67 RAM: 31 GB GPU Driver: 4.6 Mesa 24.2.6 GPU: AMD Radeon (radeonsi, renoir, LLVM 18.1.8, DRM 3.54, 6.6.67) CPU: AMD Ryzen 7 4700U with Radeon Graphics