I'll do it again. And again if needed later: 8GB VRAM utilization does not mean that card with less will be negatively affected. You can go around and pick Benchmarks of 4GB and 8GB versions of RX-580 and see if 4GB is choked. Because moment, VRAM is really not sufficient, even 200MB will have very measurable negative effect. 8GB is more than fine. And will remain in that state for next few years. By then, people will get stronger cards anyway.