The 7300 was optimized for vista. it doesn't have very good support for XP so some stuff is bugged and simply won't perform the same as it would on vista. The driver developers just didn't spend that much time optimizing the 7000 series cards for XP. They most likely just never bothered adding that XP support function to that, and they probably never will because just like a 2 or 3 year old webcam they don't care anymore, they made all of the money that they are gonna make on that product already so why produce more drivers while having to pay the people who make it a bunch of money.