............so enough with the Shakespeare already! Bringing this over from the 2004 regular forum, just to get a new opinion - although I am already resigned to OS and FS re-install.FS9 on XP, extensive payware craft, enhancements and scenery, other progs networked to laptop. I have been succesfully running the 3Gb switch for some time, thanks to good folks here on this forum,which resolved previous OOMsNow:after 90 minutes of flight CTD with "Cache directory" errors - endless streams of individual files from a whole myriad of sceneries - apparently "missing". Interestingly the missing files were on diferent continents from where I was flying at the time.Rebuilt the "scenery.cfg" - same result. But this time I noticed that after cancelling out of those endless cache directory messages and finally exiting FS, my desktop showed an .NET Framework message, quoting an "unhandled exception" (why cant Microsoft speak English when we neeed it to?) - "Out of Memory exception".Reinstalled all NET F, up to 3.5 and was efficiently bombarded by MS updates for all of it.Completed a 2 hour flight, happy.Less than an hour into a second flight - CTD - but in a big way. The most noticeable thing was that my screen resoltion was set to "you can read this from across the room" huge, with the message "Windows - Display Driver Stopped Responding".A second message: "Error during execution of nHancer" and the already familiar NET Framework "system out of memory" message.Got cross. Had lunch. Had a nap (I am 55, and I deserve a nap).Rebooted - screen resolution normal. And here I am.As I said, I am mentally preparing to take my pc to the best techshop in town on Monday, cos I recognise that its overdue a good cleaning at the very least, but even so, being without it for at least four days is not a pretty sight.I am interested in hearing any opnions from the gurus - to give me peace of mind more than anything else - althogh if anyone wants to provide a real, practical, workable and garanteed solution I would be more than gratefull !Regards to all, with thanksNicholas(Core2Duo E8500 / Intel D633BU / GeForce 8800 GTS with probably the 185.85 driver / 4Gb Corsair DDR + switch / FS on WD 7200rpm 250Gb and OS on something else / 650w PSU / ginormous Zalman cooler / Antec 900 case / wearing flipflops and underwear in Northeast Brasil)Which is prolly more information than you need.

woe, woe, woe your boaterrors on the screenmemory, memory, memory, memorycauses what you've seenI'd start with a good 3-4 hour run of Memcheck86+ to look for a bad memory stick. Trouble with multiple subsystems that aren't obviously connected (i.e. file system errors, video driver crashes etc) is often a sign of a bad RAM module.RegardsBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO

woe, woe, woe your boaterrors on the screenmemory, memory, memory, memorycauses what you've seen...

That was a good one, sir! :( Make sure your ram modules are placed in the correct slots, see mobo manual. And check each stick individually. Good luck!

Obviously I am grateful for the advice about Memcheck but its not long since I ran a full check - with 0 errors. I did this check when I was getting the OOMs on final after a long flight - and after installing the 3Gb switch everything worked fine - long flights, no error messages, no nothing - for at least a cupla months. But of course, I

Keep in mind also, that with the /3GB switch, you're forcing Windows to run in a MUCH smaller memory space than it was originally designed for--normally Windows gets 2GB of the 4GB available memory address space, and applications get 2GB. With the /3GB switch, you force Windows and all the hardware address mappings that block system memory (like your video memory) into 1GB. So if you're using a 512MB video card, half of that 1GB left to the OS is blocked by the video card's hardware mapping, and Windows is crammed into the remaining 512MB. So it might well be that you're starving the OS of memory space enough to cause these sorts of errors. You could try setting USERVA to allocate a bit more RAM to the OS. The "A" solution, which will handily solve all this if this proves the culprit, is a 64-bit version of Windows.RegardsBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO

"------------Keep in mind also, that with the /3GB switch, you're forcing Windows to run in a MUCH smaller memory space than it was originally designed for--normally Windows gets 2GB of the 4GB available memory address space, and applications get 2GB. With the /3GB switch, you force Windows and all the hardware address mappings that block system memory (like your video memory) into 1GB........"This is new to me - I didnt know that this was the result of the 3Gb switch -- I had presumed that the switch liberated more memory.So why have more memory?What would be the result of keeping just 2Gb - would everything work as well as it works now?

"------------Keep in mind also, that with the /3GB switch, you're forcing Windows to run in a MUCH smaller memory space than it was originally designed for--normally Windows gets 2GB of the 4GB available memory address space, and applications get 2GB. With the /3GB switch, you force Windows and all the hardware address mappings that block system memory (like your video memory) into 1GB........"This is new to me - I didnt know that this was the result of the 3Gb switch -- I had presumed that the switch liberated more memory.So why have more memory?What would be the result of keeping just 2Gb - would everything work as well as it works now?

Depending on how much VRAM is on your video card (and some other reserved memory for hardware devices like sound chips and other device controllers) you probably have somewhere between 3-3.5 GB of your 4GB of RAM actually available for use.The /3GB switch changes how memory address space is apportioned out--note that address space is not the same as memory. There are 4 billion-ish (4GB) addresses that can be referenced in 32 bits...half are normally given to the OS, half to applications. If you only have 2GB of physical RAM, that doesn't change the allocation of those available addresses. Windows just virtualizes them, swapping pieces of the 4GB address space in/out of physical RAM as needed.With 4GB of RAM in a computer running a 32-bit OS and a 1GB video card, 1GB of address space is mapped directly to the video card, and thus 1GB of the physical RAM can't be accessed by the system...ever. With a 64-bit OS, the hardware mapping occurs using addresses beyond 4GB, so all 4GB of RAM can be seen/used by the system. The address space available in 64-bit Windows is 8 terabytes, so the OS doesn't have to be crowded out by allowing 32-bit applications full use of the 4GB that they can address.Realistically, anything more than ~3GB of RAM in a 32-bit system is generally doing nothing but generating heat. But that said, 3GB of physical RAM can net a big performance increase over 2GB. And likewise, going to a 64-bit OS puts all 4GB of RAM into play.Clear as mud?CheersBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO

Realistically, Windows shouldn't consume more than 100-200MB for any current consumer revision of the O.S. Drivers should consume about the same amount unless you've got a ton of unique hardware with drivers whose memory footprints are extremely bloated.

Thanks for translating all the techno-babble into understandable language.My rig is as standard as it gets, with nothing special and no unusual demands on it or wierd drivers or footprints - and the 8800 GTS is only 512Mb, so hopefully my problems are caused by - - faulty or badly-placed memory sticks - a weedy and outdated 32bit system - heat build-up due to everything being covered in dust - the trouble with a good "cooler" case is that it sucks in so much s**t which sticks, rather than gettting blown out again - heat build-up due to it being in the wrong corner of the room in a city whos average temperature is 30

My pc is back in my hot and sticky hands, and with some good news.There is nothing wrong with any of the hard bits - the techguy said the dust and consequential poor contacts and heat build-up would have been enough to cause all the crashes. (Thats the trouble with having a case that sucks in air as well as pushing it out.)I can obtain, quickly and cheaply, XP 64bit in English. So ..........Bearing in mind that I will still need 32bit for other non-FS programs, can I have the two OSs simultaneously installed?Will the 64bit obviate the need for the 3Gb switch and cure the OOMs?Will it mean that FS9 uses all or at least more of my expensive 4Gb of Corsair?Will FS9 actually run any better, or will it just be more stable?Are there any known conflicts using 64bit with any of the most common FS programs or payware?Would any of you be good enough to point me at the best tutorial or set of instructions so that I can set this up?Thank youNicholas

I can obtain, quickly and cheaply, XP 64bit in English. So ..........Bearing in mind that I will still need 32bit for other non-FS programs, can I have the two OSs simultaneously installed?

Yes, in separate partitions with a boot manager to select which OS to load. BTW, users of the new nVidia 470/480 video cards are having fits with XP64 right now.

Will the 64bit obviate the need for the 3Gb switch and cure the OOMs?

Yes (/3GB switch has no effect and is unneeded in XP64), and it will cure OOMs not caused by a memory leak.

Will it mean that FS9 uses all or at least more of my expensive 4Gb of Corsair?

Not just FS9...it means everything running on your PC gets access to the entire 4GB.

Will FS9 actually run any better, or will it just be more stable?

It'll be able to run fully resident in memory, without paging. The OOMs should be history, which is clearly more stable.

Are there any known conflicts using 64bit with any of the most common FS programs or payware?

The older (2005 and earlier) versions of the RealityXP Garmins won't run because they use a 16-bit version of the Garmin Trainer. The newer WAAS versions of the RXP Garmins work fine in 64-bit. I had a few installers for FlyTampa scenery that wouldn't update the scenery.cfg file, so I just did it manually. Other than that, it's been smooth sailing, and I have a large cross section of FS add-ons here.

Would any of you be good enough to point me at the best tutorial or set of instructions so that I can set this up?

Lots out there on how to set up a dual-boot system. I use separate hard drives in external eSATA enclosures for my XP and Vista64 boot drives...I just plug the eSATA cable into the one I want and fire up the machine. I found that easier and more bulletproof than using a boot manager for dual boot.RegardsBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO

Thank you very much Bob

Lets say:I have FS set up and linked to XP 32bit on "C".When I get my copy of XP 64bit and install it on "D" where I have FS installed, (leaving the 32bit on "C" to run other programs, can I then point FS to the new XP 64 bit and have everything working (except probably quite a bit of payware which relies on reg entries)?Or will I need to reinstall FS again linking it directly to the new OS?Turns out that itll be more than a week before I can get the 64bit and thats a long time in simworld.Nicholas

Lets say:I have FS set up and linked to XP 32bit on "C".When I get my copy of XP 64bit and install it on "D" where I have FS installed, (leaving the 32bit on "C" to run other programs, can I then point FS to the new XP 64 bit and have everything working (except probably quite a bit of payware which relies on reg entries)?Or will I need to reinstall FS again linking it directly to the new OS?Turns out that itll be more than a week before I can get the 64bit and thats a long time in simworld.Nicholas

More than likely you can get FS9 to run by booting into XP64 and using Flight1's free registry repair tool to make the needed entires in the XP64 registry. Some of the add-ons, like Flight1 stuff, will need to be reinstalled in XP64 so that the appropriate key files and reg settings are made for that environment. CheersBob ScottColonel, USAF (ret)ATP IMEL Gulfstream II-III-IV-VColorado Springs, CO

Oh dear.Seeing as I couldnt wait for the 64bit OS I have just installed a very lite FS9 - meshes, UTerrains, Landclasses and some freeware scenes.I checked the paging file to its maximum recommended.No "address aware" or 3Gb switch.FS crashes on loadup with "Insufficient memory" and something that "could not be read".One thing important: I messed up and updated to FS9.1 AFTER I had done some - including switching to the "no-cd" .exe Nicholas.