I use win2k3 32bit on my modern machine with i7-4790k CPU and 16GB ram. Using a 10+ year-old OS has problems and I would love to upgrade but win2k3 is the last real version of windows. This thing has suffered numerous freezes/blue-screens, some caused by the crappy ATI drivers for my aging x300. It might be the 16GB of ram which causes the problems, the ATI drivers are not said to work with win2k3 let alone more than 4GB of ram. I like to avoid OpenGl since crashes are very likely when running that.