Microsoft last week launched release candidates for workstation and server versions of 64bit Windows, so firms can test them on 64bit extended chips.

Companies looking to run Windows on 64bit-extended chips such as AMD's Opteron and Intel's Xeon can now begin evaluating Windows Server 2003 x64 Edition and Windows XP Professional x64 Edition. Intel's 64bit Itanium is already supported by current versions of Windows.

A release candidate for Win Server 2003 Service Pack 1 is also available. It adds security updates such as the Windows Firewall and support for the no-execute buffer overflow protection in the latest chips. SP1 is also the underlying technology for the 64bit Windows releases. Full versions of all these products are due in the first half of 2005.