To give you an idea what I mean with “gets in the way”: My normal work environment takes round about 250 MB of memory just to be ready for work. None of the programs running in the background is needed for any modern game (Battlefield, Unreal Tournament 2004) but these programs eat up memory and CPU time the game desperately needs. However, the trigger to have two Windows XP installations on one computer was something totally different.
Since I need to test some of the programs I code here, I own VMware Workstation to do the testing for Windows 98, Windows 2000 and NT 4.0 in a virtual machine. Sometimes I need the original Setup CD-ROM but didn’t want the have the real discs on my desk. So I simply created an image of them and load them on demand using Daemon-Tools. Well, this works fine until I tried to start one of the games again: No-go! The anti-piracy mechanism thought Daemon-Tools to be cracker-related and thus the game refused to start. Nice. So I was stuck in the middle of nowhere to either have the game working or the Daemon-Tools working, but not both.
Once I had the separated Windows XP installation just for gaming, I never wanted to miss it again. Friends of mine always had problems when they installed new hardware or software. I do not install any drivers on the “gaming” XP I don’t need to play. TV-Card? No driver. External hard disk? No driver. Bluetooth adapter? No driver. Since fewer drivers means fewer problems, I never ever had and strange problem after that. I can test any software on my default XP without ever fearing to screw something up.
Also, fewer drivers mean less memory consumption. My gaming XP only needs 120 MB to be ready to rumble: about 130 MB more for the game.