That resolution will take a lot of vram to push. Start gaming or editing on it and it will get crushed. Most 290x's start at 4GB, why Apple chose 2GB I don't know.
Only 3090 on steam. Which is ~1/3 of the while windows back log. And a large chunk of the imported games are older games, so Linux and Mac both are making steady progress.
http://www.digitalstormonline.com/unlocked/video-memory-usag...