Windows 2000 was later corrupted by XP-ification. The primary difference was 2000 was "NT 5", where the Explorer UI appeared to be split between foreground and

Windows 2000 was later corrupted by XP-ification. The primary difference was 2000 was "NT 5", where the Explorer UI appeared to be split between foreground and background components. XP threw this away and went with the Windows 9x/ME shitshow as late as Vista. Windows Server 2003 (Whistler Server) was better than XP (Whistler) and was mostly an improved Windows 2000 (originally named NT 5 in the source code). I would generally consider using Windows Server 2003 for workstations instead of Windows XP because of its close compatibility with the latter. Windows XP Professional x64 (amd64) and Windows XP 64-Bit Edition [ia64] existed but didn't find many takers except in retro systems and niches where they had HP Itanium machines.