Firstly, XP is 32bit, and they also do a 64bit version.I doubt its any faster for production use at all. I run it on a server I have here at home. Its loaded with more features for networking and administration. Plus you cannot use 32gig of ram in the 32bit version. You can use up to 128gig of ram in XP 64. I have an XP 32bit machine here and it boots up in 14 secs, and shuts down in 5. It all deppends on how well you strip down and optimise your O/S. Personally i wouldnt reccomend 2003 for production, plus the licence for it costs a bomb.