The good news is that render targets on pretty much every newer GPU are compressed and aren't eating the full VRAM cost or even the full bandwidth cost. AMD has a good overview here. Nvidia does something similar for much longer already (around Fermi times, potentially even before with Tesla). In any case, render targets aren't that expensive anymore these days.

Although I guess one big problem with Gamestudio is that it's 32bit so not only VRAM is a concern.