Ooh, fair enough then.
XP covers a *wide* era of retro gaming though, I've seen people use it Pentium 3's and Voodoo chips right up through Core i7's with GTX 950's
What's the "expected" OpenGL version the engine is targeting? The GTX 7900 in my machine can do up to OpenGL 2.1 and Shader Model 3 which is pretty ancient