out of these two options what will give the best performance?

I am new to this and a week or so ago I setup a local ai box, it is an amd 9950x with 64gb ddr5 6000 ram, 2 rtx 5090s (on motherboard that does pcie gen 5 x8 per card). It is working fine but I have been running flash next the past days and of course it is slower than 3.8 27b, although it is not too bad. So my question is, I have my proxmox server, which is an epyc 7402p cpu, 256gb ddr4 ecc 3200 (8 channel) on a supermicro server board with plenty of pcie gen 4 16x slots (so same speed as the gen 5 pcie 8x the cards are currently in). Will having the extra system ram, also being 8 channel ram help out enough to warrant going through trying to get the 5090s installed in there? It is a large 4u case but not sure there is enough room. Also will it run perfectly fine and fast through a vm in promox with the gpu's passed through?