Speaking at last week's IT Forum in Copenhagen, the Microsoft chairman said the transition would be smooth thanks to binary compatibility between the two processor architectures.
"This will provide the ability to mix 32-bit and 64-bit [with] a very simple recompilation for any application you might want to run, using the full 64-bit address base," said Gates.
With 64-bit Windows, "even the most expensive mainframe will not deliver the performance that industry-standard hardware running Windows will deliver," he added.
"The work Intel and AMD do at the chip level means the 64-bit capabilities are going to come into your servers with no premium in price. The same type of pricing with the servers that you have today will be available with 64-bit capability."
Microsoft also announced it was developing a smartcard based on its .net programming framework. With .net, users could incorporate information onto cards using the same development tools as corporate developers, according to Microsoft.