Hmm, I'de advise even XP x64. The driver support is still rather lax. Also it really dosn't offer a huge advantage over normal XP. If you were going to run a 64 bit OS, a x64 Distro of Unix is the best way to go.
Cheers
Cameron
I think you better re-install XP x64 with SP2 that just went gold Cam
They completely replaced the HAL. It was smoother than x32 before the upgrade if you had the right drivers but now that dual core support and video sub system HAL has been replaced, I would not run FSX on anything else (at least with AMD, I can not vouch for Intel because I have not tested it as of yet but in the process soon). Its not a miracle jump in performance so please, anyone reading this dont run out and buy x64 unless you want to try it... then get the trial version before you decide.
NOTE: For full x64 SP2 support you MUST slipstream the original x64, x64SP1 install with SP2 and clean install the OS off the slipstreamed disk. The UPGRADE does NOT completely replace the HAL and other sub systems and -may- force some issues to the surface on certain chipsets. The upgrade does work however most sysadmin's are slipstreaming for maximum efficency and upgrade success
x64, in my opinion, now ROCKs
I have been playing with SP2 x64 since last September and it has come a long way. Dual core hotfix and optimizer are no longer required.