I guess I should add that this computer will be for Zwift only. I have my "main" computer in a room in the house that is separate from the room I have my bike and trainer set up. So, I'm not really concerned about running other programs (I do my photo and video editing on the main computer, along with just about everything else including CAD)
What about getting a newer computer (possibly a refurb unit with SSD, sufficient memory, crappy video) and upgrading with a better video card?