I've seen linux apps in 64-bit looking a lot more promising than their windows counterparts. Many apps average a 20% improvement over 32 bit. I have no doubt that the same potential is there for windows. The problem is an issue of effort. Linux is written by geeks, for geeks (no offense to anyone, as I'm a geek, too). Linux geeks with 64 bit chips likely put lots of effort into making their 64 bit apps run great, and taking full advantage of the new capabilities. Theres is also no shortage of manpower to make this software, as linux developers are doing it for FUN. As a result, 64-bit linux is great. Windows on the other hand, is written by a corporation, for the market that will make it the most money. The market is 99% 32-bit right now, so 99% of microsoft's efforts are devoted to 32-bit windows and plugging all the security holes therein. Since microsoft is a company, they have limited resources, and when 32-bit windows has a problem, people get taken off the 64-bit project to help fix the 32-bit product. Plus, driver support is the same way. ATI's drivers didn't exist for a long time, and even now they are beta. When Intel starts moving more 6xx processors, expect development to take more of a priority, and performance to go up.