The architecture of the k80 just doesn't allow memory sharing or pooling. The newer systems (Pascal and above I think?) can allow it on the right hardware but it's all datacenter and workstation cards for that.

Man, feel like I shoulda picked up the M40 instead then, since it was 24 GB VRAM in total. :(

Oh well, I've spent $90 on dinners and had far less fun than I will have with this video card when it arrives, so I can't say it was wasted money... and I can always just buy an M40 off eBay.

If RTX 3090 prices keep dropping through the floor, I may just bite the bullet and pick one up. I saw a ZOTAC on sale for $999 recently, which is $500 less than the launch MSRP of $1499 (which honestly is where it should have launched anyway... so far as I'm concerned, these cards only just now hit reasonable pricing).