@billymild 1 GB access for limitation for the GPU. the CPU has access to the full memory.
i'm not convinced that any viable emulation task would ever get near 1GB GPU memory, though. i believe the internal bandwidth of the pi and various bottlenecks in the GPU would make framerates a crawl at the kinds of tasks that need 1GB VRAM , regardless.
realtime VRAM usage used to be easy enough to measure: sudo vcdbg reloc - presume this doesn't work correctly on pi4, though.