To the OP:
The Intel GMA 950 isn't designed for any 3D work really. It's great for 2d work, playing a DVD, and that's about it really. Since you're interested in a Mac Mini, I would suggest getting the 2GB of RAM with it. An actual GPU would be nice, but it's not an option with the Mini.
To V8VENOM:
If you will read, we find it funny how someone is considering an integrated card an upgrade when in reality it's a downgrade. That's what most of us were commenting until your "intelligent" response. Also, considering this is a PC/Hardware forum, what do you expect? I for one like building my computer with the hardware I selected which you can't do with Mac.