Well OP asked where an rx580 would use 16gb of vram , and I gave him an example from my experience. If you think I would recommend anyone to buy a 16gb rx580 for gaming my answer is hell no.

For stalker though a hi res texture pack really helps visuals a lot. Since the original game/assets are from 2010.

Stalker Anomaly with a texture pack would do it, my 8gig rx580 gets around 7.5gb used up playing it at 1080p.