Textures are going to be your main memory issue (at least for the graphics card). One instance of an object should share the texture of another instance of that same model. For reference, the HW2: Warlords models have textures normally around 1 MB to 5 MB. The highest is the Sovereign, something like 27 MB. Given decent mid-range cards now hold 256 MB, 512 MB, or even 1 GB of video memory, I don't think you'd reach that limit, esp if you're rendering what is essentially a space background with some ships. If we were talking a complicated 3D FPS with walls and floors and trees and monsters, yea you may definitely exceed that limit. Of course you do have to worry about how fast the video card can process. You may end up with having to deal with how many vertex or pixel shaders are needed. Older cards are limited that way, while newer cards have more generic programmable shaders to handle either case. Still there is a finite limit on how many vertices or pixels you can process and still make it playable (30 FPS or larger) (I realize I used FPS twice.. one as First-person Shooter and the other as Frames-per-second hehe)