While I understand your attempt to help, it really doesn't make any sense considering I run countless other addons including FSDreamteam JFK, Frankfurt X (crashes before their acceleration patch) and others that ONLY getting OOM and dll crashes at Amsterdam X and Brussels X all by the same company makes it hard to believe anything other than something is wrong with their scenery. Missing textures, corrupted, something with their scenery.

Well you might be interested in knowing that I just now completed a flight into London Heathrow by UK2000 (the demo version that I'm trying out) and ALMOST had OOM. How do I know this? Because just on my final, about 3-5NM from touchdown, I started getting those spikes and then the entire scenery started turning into cubic/geomeric shapes and I basically could not see anything. I immediately paused FSX, ran the memory defrag from system Mechanic and was able to see the scenery again and to continue the flight. But you're right in that Aerosoft scenery IS known for its slow framerates across the board. I have Amsterdam X and CDG X and the frame rates for these are about 50% less than the Heathrow by UK2000. The multitude of add-ons we use in FSX also compound the memory problem. I was using Radar Contact 4 for this flight to Heathrow (from Zurich) and after ATC tells you to taxi to "ramp", RC basically ends its job there. After I closed RC, my frame rates went from 8fps (taxiing) to 12-16fps. So if you have that many add-ons - especially utilities like RC or others like Ultimate Terrain, etc..., it seems to be that you may have reached a "saturation point".Just my two cents worth. Take it or leave it.

This was my setting for the longest time, John - with a 1gig gpu and 32bit XP Pro, and it should work just fine for you. Note (you probably are aware of this anyway) - you do need FSX SP2 or Acceleration installed OR you need to make FSX.exe LargeAddressAware by using CFF Explorer.

I just found the core articles from the Microsoft support knowledge base regarding Windows XP 32-bit and how to use the USERVA and 3GB switches. The explanations in Nick's articles were unclear and vague about the mechanism of Windows XP's design and what maximum memory it really does end up using and how 3GB switch really works. Microsoft's explanations are much clearer. Here is a copy paste quote from Microsoft:(1) You can use the /userva=xxxx switch for more precise tuning of user and kernel virtual memory space in the Windows Server 2003 family. Use this new switch with the /3GB switch in the Boot.ini file to tune the User-mode space to a value between 2 and 3 gigabytes (GB), with the difference (3,072 less xxxx) being returned to Kernel mode. Note that xxxx is expressed in megabytes (MB).The following sample Boot.ini file demonstrates how to use the new switch to tune a computer to allocate 2,900 MB of User-mode virtual memory and 1,196 MB of Kernel-mode virtual memory. This increases the available kernel space by 172 MB: [boot Loader]Timeout=30Default=multi(0)disk(0)rdisk(0)partition(2)\WINNT[Operating Systems]multi(0)disk(0)rdisk(0)partition(2)\WINNT="Microsoft Windows Server 2003" /fastdetect /3GB /Userva=2900(2) The /userva=xxxx switch is designed to allow for more precise tuning of User-mode address space for program manufacturers who require more than 2 GB of User-mode space but do not require all the space that is provided by the /3GB tuning switch alone.Note Using only the /3GB switch allocates 1 GB to the kernel and 3 GB to the User-mode space.Using this switch reduces the memory available in the following system pools:Nonpaged Pool Paged PoolSystem Page Table Entries (PTEs)(3) Note Microsoft Product Support Services strongly recommends using a range of memory for the /userva=xxxx switch that is within the range of 2900 to 3030. This range is wide enough to provide a pool of system PTEs that is large enough for all currently observed issues. Typically, a value of 2800 for the xxxx placeholder will provide close to the maximum available number of system PTEs possible. Values observered in production for the 2800 setting are usually in the 50,000 - 70,000 free system pages, more than enough for all installations. If the value is less that 24,000, you should reduce this value in 64 MB steps until values larger than 24,000 to 26,000 are observed. Smaller numbers in the userva switch result in larger allocations of system pages. So basically, my 4GB of RAM will be used by Windows. This is what confused me in the first place. I should have checked the MS KB a long time ago to confirm all these discussions in these forums which are misleading. ** TO CLARIFY: WINDOWS XP 32-bit DOES USE AND SEE UP TO A TOTAL OF 4GB OF SYSTEM MEMORY. If you use just the /3GB switch in your boot.ini file, Windows will allocate 3072MB to applications, eavling 1024 for windows itself. If you add the /userva switch, then you can CHOOSE what amounts to allocate to the virtual address space used by applications and how much is left over for windows.I will try a /3GB switch by itself (which is the same as using /userva=3072) to see how FSX performs and post back here. Cheers!JohnNOTE: the original Microsoft KB article can be found here: http://support.microsoft.com/kb/316739/

** TO CLARIFY: WINDOWS XP 32-bit DOES USE AND SEE UP TO A TOTAL OF 4GB OF SYSTEM MEMORY. If you use just the /3GB switch in your boot.ini file, Windows will allocate 3072MB to applications, eavling 1024 for windows itself. If you add the /userva switch, then you can CHOOSE what amounts to allocate to the virtual address space used by applications and how much is left over for windows.

You are forgetting devices (such as your video card) that have on-board memory that is mapped into the address space reserved for system use. This "shadows" system memory in the same space, meaning that you will never see 32-bit windows using all 4GB of system memory.Here is a link to a sample Microsoft KB article: http://support.microsoft.com/kb/929605#appliesto

You are forgetting devices (such as your video card) that have on-board memory that is mapped into the address space reserved for system use. This "shadows" system memory in the same space, meaning that you will never see 32-bit windows using all 4GB of system memory.Here is a link to a sample Microsoft KB article: http://support.microsoft.com/kb/929605#appliesto

Yes, thanks Tom, I see that now. In fact, after posting my previous discussion, I tried FSX without the userva= switch, with just the /3GB switch and seem to have issues getting a proper view: My panel in the PMDG 744X basically disappeared to show just a black area, in 2D panel mode. The virtual (3D) cockpit mode, all seemed fine. I just tried the /userva=2812 switch and it seems OK but not perfect. It get a distorted trail of white smoke behind my 744, which is in the form of straight spikes and geometric lines, rather than true "misty" smoke. I had gotten this before, even before I had purchased my new ATI/SAPPHIRE 5770 1GB video card so it does seem like this may be one of those "artifacts" or issues one sees when the system is low on memory. What do you think?John

So basically, my 4GB of RAM will be used by Windows. This is what confused me in the first place. I should have checked the MS KB a long time ago to confirm all these discussions in these forums which are misleading.

John, You are getting closer in your understanding, but you are still confusing RAM with address space.Your 4 GB of RAM has nothing, I repeat nothing to do with this whole discussion.This would all be equally valid if you had 2 GB of RAM installed.

John, You are getting closer in your understanding, but you are still confusing RAM with address space.Your 4 GB of RAM has nothing, I repeat nothing to do with this whole discussion.This would all be equally valid if you had 2 GB of RAM installed.

Hi Bert,The application address space, as far as I understand from the MS articles, CAN address memory address table address ranges ABOVE 2GB with the /3GB switch. The HIGHEST 1GB (1024MB) or more, if one uses the /userva= switch is reserved for operating system use and any other system-installed devices. This would include not JUST the video card, but I the sound card (other PCI devices) and system devices integrated on the motherboard like the network card. So I need to give the system portion considerable more than just 1GB since my video card is already (possible) using UP TO 1GB of the memory address space. I had read that XP needs somewhere around 490MB (or probably more) for itself. Anyways, the other issue is apparently that, again, if I understand accurately, in 64-bit OSes, applications (and hopefully this includes the 32-bit apps that we use for FSX (and addons) do NOT need a CONTIGUOUS block of 1MB of memory always reserved. It is on a first-come, first-serve basis, and I assume this also means that the applications will take what memory they need even if it is less then 1MB (in 64-bit Windows). If one has only 2GB of RAM, then the total address space is also less obviously, so what you're saying is a bit confusing. Is this basically the idea?IN any case, I'll be doing another flight today using only the built-in weather program of FSX, Radar Contact 4, PMDG 744X from a default airport - Munich, to the Aerosoft Amsterdam X. The final approach and landing at Amsterdam will be the real test, as well as the taxiing.

If one has only 2GB of RAM, then the total address space is also less obviously, so what you're saying is a bit confusing. Is this basically the idea?

I believe the address space is independent of physical memory = RAM. :( 2 GB installed, 4 GB installed, 6 GB installed, same address space.32 bit OS or 64 bit OS: different address space. Other than that you are getting closer to the story, as I see it.

I believe the address space is independent of physical memory = RAM. :( 2 GB installed, 4 GB installed, 6 GB installed, same address space.32 bit OS or 64 bit OS: different address space. Other than that you are getting closer to the story, as I see it.

Well, I also applied the graphics shader "upgrade" from ******* Altuve which is supposed to make a significant difference in ATI card performance since apparently, the older FSX engine uses older shader engine versions. I have also reduced the AA and AF in my ATI settings. At Mega Amsterdam X by Aerosoft, the framerates on the ground at the gate are now around 12-16 FPS instead of 8-10 fps before.I did some test "go around" flights around Amsterdam and other airports yesterday and the frame-rates are better. But I have not implemented all of the FSX.cfg settings of ******* since I am unsure if they are for all systems or specifically for Windows 7 64-bit.I will do a full flight today with Radar Contact and Active Sky Evolution (ASE) and see how it goes.Obviously, I am concerned that memory will still be an issue in 32-bit WinXP as everyone has mentioned. I am just rather weary of going back to the "other can of worms" that is Windows 7/64... I'll be deciding on this later. But the address space can be expanded with the 3GB switch-that's the whole idea of having /3GB switch with the /USERVA=xxxx in the first place. But in a 64-bit OS, the memory management of the address space is much more dynamic (first-come-first-serve basis from what I've read) than in 32-bit OS. I don't really know how big the address space is in Win 7 /64 but you don't sound too sure yourself. I will try to read up on this or even ask my friend at work who is a programmer (and so is her husband actually) and teaches OS theory in university.Thanks for all your suggestions and input.John

FSX is rock solid for me in W7 64 bit. After tweaking it properly it literally never crashes. Most important tweak for me was the uiautomationcore.dll tweak, and of course never using DX10 preview. Maybe I'm just lucky with my addons that they dont crash FSX. I dont know

From what I see here, http://news.techworld.com/operating-systems/3212968/over-90-of-windows-7-pcs-max-out-on-memory/the problem is with the Windows 7 operating system and not your flight sim program.I am still waiting for MS to get these bugs worked out before leaving XP.Terry

Well, here I am, after a "test" flight from EHAM to EGLL. Both are payware complex high-resolution texture airports. Mega Airport Amsterdam X by Aerosoft and London Heathrow X by UK2000 (demo). First my setup of what apps / addons I was running: PMDG 744X (British Airways colours), Active Sky Evolution Build 572, Radar Contact 4.x. Flight plan was done with my usual planner-FSBUILD.No issues at all at Amsterdam. But the weather at Amsterdam, and in fact in London also, was mostly sunny with patches of clouds, though it seemed to rain anyways in Amsterdam, even though there were scattered clouds or even few clouds but that's ASE-never mind that. The PMDG 2D cockpit was perfect throughout the entire flight - no "skeleton" cockpit but this WAS a short flight and... wait until I tell you what happened at my final to Heathrow. The same things happened on my final to Heathrow, with about 5-10NM left to touchdown, I get most if not all of the scenery being blotched out with brown, grey geometric shapes and fuzzy stuff - basically I could not see anything out of my cockpit. Even switching to external views had the same disappearing textures/blotches. All the while, as before, the PMDG panels worked perfectly, including the overhead panel, FMC, clock, communications radio panel etc...So I did what I had done before - simply MINIMIZED and then MAXIMIZED FSX using the ALT-TAB keys. The blotches completely disappeared and I continued to a perfect touchdown. I taxied for a good 10 minutes to terminal 4 (gate 410) which is a far way from runway 27R and had no problems.The framerates were actually great. They were in the mid to high teens and even 20's, even during taxiing to gate 410 at Heathrow. At Amsterdam, as is typical it seems with Mega Airport Amsterdam, the frame rates were slower - around 12-16fps when taxiing, dipping to as low as 8fps but smooth, without stutters nor choppiness. After ending the flight, I tried to resume from save with Radar Contact. After multiple attempts, I finally got it to resume (RC is a MESS when resuming from save or the instructions are very vague and I don't understand them but FSX needs to be open, then RC freezes etc...). When I resumed I had NO 2D panel. The area of the 2D panel was completely BLACK. If I looked left / right - the cockpit was visible and back also. After restarting FSX, and resuming again the flight from the closest approach point, I finally got my panel but when I switched to the overhead panel, I got a compressed mess of things. I could not see anything clearly - the overhead panel was basically corrupt. But I minimized and maximized FSX AGAIN and got back my overhead panel. But this time all the virtual cockpit views (looking L, R, Back, side) had gone and all I could see was the scenery and no cockpit. The front 2D panel was fine.I checked my memory usage and it reached around 2650MB total used in task manager. So the memory issue remains. I think I will have to try reducing my settings again and if that fails, I will install a second copy of FSX (if it works) in Win7 and do some testing.Any comments anyone? I would much appreciate the insights especially of those of you with lots of tweaking and FSX "suffering" experience... :( Cheers!John

From what I see here, http://news.techworld.com/operating-systems/3212968/over-90-of-windows-7-pcs-max-out-on-memory/the problem is with the Windows 7 operating system and not your flight sim program.I am still waiting for MS to get these bugs worked out before leaving XP.Terry

There are 2 things being mixed up in this discussion.1) Real memory : the real sticks of memory you put in your computer2) Addressible space : a problem of 32bit or 64bit (or even 128bit) and is defined by how many computer bits are used to define the unique memory location for a variable in memory.Addressible space : results in Out of memory errors. : 32bit computers can onlyaddress 4G of memory - whether real or vitual, even if you put 8G of real memoryin your computer, it can only ever address 4G and will ignore the rest. 4G approx = 2^32 (2 to the power of 32 - ie 4 billion unique values)This 4G is shared by your computer program (FSX/FS9) and your computer OS (windows)and the graphics card - the driver space - but is a shadow of the memory used inthe GPU. Normally this is set to be 2G program space + 2G system space, but youcan change this - at your peril - and can give nasty problems if you don't leaveenough space for your graphics card.Finally, FSX is a 32bit compiled program - so the program varaibles can only have4 billion different values (4G), so FSX/FS9 can ONLY use 4G of memory on a 64 bitmachine. IT does not matter how much real physical memory that you put in yourcomputer - FS9/FSX cannot ever use more than 4G of memory. Remember though, yourgraphics card and OS need space, so you might consider 6G of physical memory ina 64-bit OS machine as this will allow fsx/FS9 to use 4G and leave space in physicalmemory for graphic/OS to play.The first issue, or is that my second issue. The aggressive use of physical memoryin vista and Win 7. It is generally a good idear that an OS use as much physicalmemory as possible, as it take time to load memory from disk. So if you have a program loaded in memory (even if it not running), it will start quickly.The problem discribed in the last link is an issue for people that use multipleprograms - if the OS is too aggressive with loading physical memory just in casethen other programs become slow to load and start. This is NOT a problem for this community as they probably use their machine mostly for FSX/FS9, and so it becomes quick to start a second time as most of thephysical memory is in use and filled up with FSX/FS9. This has nothing to dowith out of memory errors (a property of addressble space), but an issue of loadtimes. Sorry - probably should be in hardware....Hope that helps.

There are 2 things being mixed up in this discussion.1) Real memory : the real sticks of memory you put in your computer2) Addressible space : a problem of 32bit or 64bit (or even 128bit) and is defined by how many computer bits are used to define the unique memory location for a variable in memory.Addressible space : results in Out of memory errors. : 32bit computers can onlyaddress 4G of memory - whether real or vitual, even if you put 8G of real memoryin your computer, it can only ever address 4G and will ignore the rest. 4G approx = 2^32 (2 to the power of 32 - ie 4 billion unique values)This 4G is shared by your computer program (FSX/FS9) and your computer OS (windows)and the graphics card - the driver space - but is a shadow of the memory used inthe GPU. Normally this is set to be 2G program space + 2G system space, but youcan change this - at your peril - and can give nasty problems if you don't leaveenough space for your graphics card.Finally, FSX is a 32bit compiled program - so the program varaibles can only have4 billion different values (4G), so FSX/FS9 can ONLY use 4G of memory on a 64 bitmachine. IT does not matter how much real physical memory that you put in yourcomputer - FS9/FSX cannot ever use more than 4G of memory. Remember though, yourgraphics card and OS need space, so you might consider 6G of physical memory ina 64-bit OS machine as this will allow fsx/FS9 to use 4G and leave space in physicalmemory for graphic/OS to play.

Hello TomOOO,Yes, this helps clarify things a lot because of the concise manner in which you explained everything. Now I understand why people with Win7 64-bit have 6GB or more of RAM in their PCs. I may want to explore this option. I may add 2x1GB more of another matched pair of Kingston HyperX of the same MODEL as the ones I have in my PC now, to make a total of 6GB and use Win7 64-bit. I think my bad experiences with Windows 7 back in February were because of many things. First, there was not enough knowledge about Win7 and FSX interactions as it was very new (only on the market for 4 months at the time). Second, my memory was 2x1GB 9-9-9-24 (Corsair) and my graphics card was a very slow 8600GT with 256MB of video memory. Now I have an ATI 5770 with 1GB video RAM (which is overkill for FSX but may be good in the future), 4GB of 7-7-7-20 memory and a much better knowledge of what others are doing to tweak their Windows 7 64-bit systems with FSX. For now, I will reduce my screen resolution from 1920x1080 to 1680x1050 in Windows XP 32-bit, set my video driver to use application settings (if the quality is acceptable to me in FSX scenery) and wing it, until I can upgrade my RAM and then try re-installing FSX in Windows 7/64.Thanks again for your very helpful and clear summary.John

Hello TomOOO,Yes, this helps clarify things a lot because of the concise manner in which you explained everything. Now I understand why people with Win7 64-bit have 6GB or more of RAM in their PCs. I may want to explore this option. I may add 2x1GB more of another matched pair of Kingston HyperX of the same MODEL as the ones I have in my PC now, to make a total of 6GB and use Win7 64-bit. I think my bad experiences with Windows 7 back in February were because of many things. First, there was not enough knowledge about Win7 and FSX interactions as it was very new (only on the market for 4 months at the time). Second, my memory was 2x1GB 9-9-9-24 (Corsair) and my graphics card was a very slow 8600GT with 256MB of video memory. Now I have an ATI 5770 with 1GB video RAM (which is overkill for FSX but may be good in the future), 4GB of 7-7-7-20 memory and a much better knowledge of what others are doing to tweak their Windows 7 64-bit systems with FSX. For now, I will reduce my screen resolution from 1920x1080 to 1680x1050 in Windows XP 32-bit, set my video driver to use application settings (if the quality is acceptable to me in FSX scenery) and wing it, until I can upgrade my RAM and then try re-installing FSX in Windows 7/64.Thanks again for your very helpful and clear summary.John

FYI : I am using win 7 64bit home premium and have no problems with FSX and haveseveral addon.There is a final addendum to my post : Microsoft make different versions of Win 7,and they set the limit of the physical memory usable in the different versions. Win 7 basic 64bit : only 2G !!!!!Win 7 premium 64bit : 16GWin 7 professional 64bit : 128GIe don't ever use win 7 basic - they block the usage of physical memory to only2G which is not going to play well with FSX. finally, finally - I guess that the next version of Microsoft flight will be 64bit,and then you will be able to have 2T of memory - but then every single addon thatuses a DLL will not be compatible. :)

FYI : I am using win 7 64bit home premium and have no problems with FSX and haveseveral addon.There is a final addendum to my post : Microsoft make different versions of Win 7,and they set the limit of the physical memory usable in the different versions. Win 7 basic 64bit : only 2G !!!!!Win 7 premium 64bit : 16GWin 7 professional 64bit : 128GIe don't ever use win 7 basic - they block the usage of physical memory to only2G which is not going to play well with FSX. finally, finally - I guess that the next version of Microsoft flight will be 64bit,and then you will be able to have 2T of memory - but then every single addon thatuses a DLL will not be compatible. :)

Helo TomOOO,Well, I just added to my post from February, in the Win 7 OS forum, that I had a perfect flight from Aerosoft Mega Airport Amsterdam to UK2000's Heathrow X with the PMDG 744 in Windows 7 64-bit. I have not even done any tweaks yet to the fsx.cfg. The big difference for me, from February to now, was most likely my much more powerful video card - I went about 4-6 week ago, from an Nvidia 8600GT 256MB to an ATI 5770 1GB. John