Vista 64 and Win7 64 will be supported once the 64 bit version is out. XP 64 is not and will not.
(Aha, found the proof.)
That's good to know... gives me a reason to triple boot my home gaming system with the Win_7 64Bit version.
Once again, XP 64. These reasons apply to consumer versions of Windows, like Vista 64 and Win 7 64. XP 64 was an extremely limited release intended for very specific professional usage scenarios, and for driver writers to have something to start working with before Vista. It was never pushed or intended for home use, and support was largely discontinued pretty quickly (officially it was along with normal XP, but normal XP was really better about being supported).
For various reasons, some people wound up with XP 64 on gaming machines, but that's a usage situation that is pretty oddball and not guaranteed to work.
The Win 7 64Bit version was not around when I was building my home system and the Vista_64Bit version not only has problems with some of the older games, but would have taken more time tweaking thus I selected to install the XP64Bit version. While the XP64Bit version was never intended for gaming it works perfectly for all my RTS, TBS and RPG games. The 'extremely limited release' must be a city retailers reference because it's quite easy to find and purchase a legit copy online. Luckily due to my career I never need to purchase the operating systems.
Well to be precise, Vista and Win7 are supported in both 32-bit and 64-bit no matter what. The difference is that we are working on a native 64-bit version as well but the 32-bit version will also work.
XP 64-bit isn't supported but I imagine the 32-bit version will work.
Excellent news... I'll setup my home system to triple boot with Win_7 64Bit version to assist with the beta testing of very very large maps. I love how Elemental will have maps which will truly be large enough to be a world... playing a single game for weeks before encountering your first AI opponent.... the armies, magic, and terrain will provide a very intense experience.