(Moderator: Posting this under the Hardware Forum as well since that's where I first read about the advantages of a 64 bit OS): Using FS9, XP Pro 64. All sliders right, AI at 70%, all other addons identical.I've been having more than my fair share of OOMs and CTDs in XP Pro 32 so I've done a clean install of XP Pro 64 bit edition on a new Seagate 500 GB 32 MB Cache drive, and then a clean install of FS9 and at FS Dream Team's KORD I get 7-9 FPS with the 64 bit OS whereas if I boot back into the 32 bit XP Pro I will get 21-24 FPS.Over clock settings are identical, I don't change them in the BIOS. My 32 bit OS and FS9 install IS on a 10K Raptor, but I certainly don't think that would make my sim fly 66% faster frames? (It will be easy enough for me clone the Seagate to my Raptor, but I want to make sure that's not the issue.)Has anyone else have this experience? Is there a basic tweak I missed or need to do to XP PRO 64 before I really get to flying in that OS? Or is it really not basically appropriate for FS9?Thanks for any insight anyone can provide before I go back to square one and do ANOTHER fresh install.

I'm using FS9 on Vista 64 and it's only running 1-2 fps slower than XP32, but much smoother and without OOM headaches. I know of others using XP x64 with similar results as mine.I'd recommend getting the latest DirectX update and the latest drivers for your sound/video as well. Drivers are making progress in leaps and bounds in the 64-bit world lately. And of course the usual steps of killing off unnecessary processes with AlacrityPC or equivalent is a good idea in case there's something like file indexing going on like mad in the background.CheersBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO

Thanks, Bob. It didn't even occur to me that 64 bit would run any slower at all. Any idea why? I have a lot of add on scenery and I may be able to control the OOMs and CTDs over on the 32 bit side than I can the Frame Rate hit with airports like KORD and KJFK.

Well, it's not just 64 bit, it's Vista 64 bit. So there's lots more overhead associated with security etc. But the speed diff is trivial, and in heavy scenery it actually performs better than 32-bit because it can load everything into memory without much, if any, paging of texture files.The OOM thing in 32-bit with complex acft/sceneries (PMDG 747 in particular) was nearly enough to put me into an Incredible Hulk stomping rage at times...the stability and reliability increase made rebuilding Rome on 64-bit sand more than worth the trouble. I am keeping my 32-bit system alive (on a separate swappable external HDD) for some of my GA birds that can't make the trip to 64 (i.e. Piper Meridian and lots of my GA birds that have been retrofitted with RealityXP gauges that need the 16-bit WOW subsystem).CheersBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO

>>Well, it's not just 64 bit, it's Vista 64 bit. No, I'm asking about XP 64 -- I made a conscious decision to stay with XP because of all the overhead in VISTA -- and the questionable availability under VISTA of some of my older FS9 add-ons.>>The OOM thing in 32-bit with complex acft/sceneries (PMDG 747 in particular) was nearly enough to put me into an Incredible Hulk stomping rage at times...Oh, man, can I identify! Did you ever notice that it always seemed to happen on late final? -- Never right at start up! :-lol In any event, I think I finally got it straightened this morning about 1:00 AM (I'm a New England Patriots fan (**sniff**) so I was up after the game anyway).It was my bloody Dual Head To Go "Desktop Manager" autoload conflicting with ATI's CCC manager software from boot up. I had set up FSAutoStart to shut both processes down, but I guess it never fully executed the commands. As soon as I blocked both Matrox .exe's from loading at boot, my CPU temps went back down to mid 40s C and FRs came back to within 2 or 3 of my 32bit install. :-jumpy I'm keeping my 32 bit FS 9 alive on a separate drive as well. We've worked too hard to take any chances now, eh?

Bingo...I knew there had to be some explanation.The first time you shut down at the gate after a 6-hour flight through complex sceneries without a hiccup, it might still take a few minutes to realize what just happened.It didn't take but a couple of flights like that before my 32-bit XP setup started feeling neglected.Sure makes life a little easier!CheersBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO