Speaking at the Intel Developer Forum, Windows chief Jim Allchin said the desktop version of the souped-up Windows would come at the beginning of April, while the server version would come at the end of the month.
"We're locked on to 64-bit," Allchin said, encouraging developers to start tailoring their applications to include the ability to take advantage of the extra processing power.
Last month, Microsofta second, near-final "release candidate" version of the operating system. The company had promised a final release would come by the end of June.
The 64-bit versions of Windows XP and Windows Server 2003 have been, particularly for chipmaker Advanced Micro Devices, which has offered such chips for roughly two years in the server market and 18 months in the desktop PC market.