Any Doom 3 players know if the demo has gimped performance? I know what to expect (in other words, not much), but I ask because the Unreal demos are usually like this. When you install the full version you get like 2x the framerates. My impression so far on my machine is that, while it will run just fine, for the purposes of any respectable Doom fan, it's clearly not worth it. It's not looking good for Quake IV.