Comment # 61 on bug 82050 from Michel Dänzer

Note that some of the Unreal Engine 4 demos want to use more than 1G of
graphics memory (as shown by the GALLIUM_HUD queries requested-VRAM and
requested-GTT), so if the GPU has 'only' 1G of VRAM or less, that's a very
difficult situation for the graphics memory management code.