FSXCYYZEGLL

FSX OOM even with 1GB Free VAS

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So to start off this thread I have tried multiple times from various long haul flights to try and fly the pmdg 777 into toronto pearson with only the Ray smiths Addon airport installed, I have a VAS monitor and look at it each time I try and go in, sometimes I am even looking at it when the OOM error occurs, the max the VAS monitor ever said it got to was 3.5 gb of vas usage, and the one this morning was at 3GB of VAS usage when the OOM occurred, so I've got to ask what is going on(I have a 64 bit windows and 16GB of RAM by the way). the VAS monitor I use is Process Explorer 64. This really doesn't make much sense to me, the addons I've got are the PMDG 777-300er, Activeskynext, and GSX. Those are the main ones with no scenery addons besides Ray smith's airports. So why am I getting an OOM even when my memory or VAS isn't fully used seeing as the memory used in this OOM was 7GB out of 16 GB, is there any reason why FSX is now not even taking 4GB of memory. Or is my VAS monitor getting it wrong?

 

Signed Jon Alexander

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Short answer is that FSX is (unfortunately) a 32 bit application so it is only ever able to address a little over 3.5 GB of memory.  I have a machine with 32 GB of memory and I can get OOM errors in FSX.  I'm not sure what the solution is besides more CPU and larger faster SSD's so that Windows can page memory out to the hard drive.

-HughVFR

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Perhaps try Steam Edition? I'm sure I've read somewhere (LOL I know...) that it tries to recover some VAS as the flight progresses...

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3 minutes ago, HighBypass said:

Perhaps try Steam Edition? I'm sure I've read somewhere (LOL I know...) that it tries to recover some VAS as the flight progresses...

I'm using FSX SE and most of the time it doesn't crash for me, so I'd hazard a guess that your notion is correct. If it weren't true, FSX SE would be crashing with OOM's an awful lot.

-Hugh

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32 Bit means it can access all the way to 4GB, which is what many people report OOMs occurring at, my question is why is the OOM occurring at 3GB of Vas, I know the 4GB limit. Im just confused as to why it is OOMing at 3GB when it still has plenty to access even for a 32bit program.
 

Signed Jon Alxander

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The OOM solution is a 64bit flight sim - if you must fly the PMDG 777, then Prepar3D version 4 (64-bit) is your only option. Even if you are only getting to a reported 3GB VAS - there may be a millisecond spike over 4GB and that is why a 64 bit flight sim has been so necessary for the last 10-20 years.

I have flown the 777LR from EGLL to YSSY to KLAX to KJFK, and finally to EHAM trying to get Prepar3D version 4.1 to crash, and over 4 days it would not crash. I use GSX and ASv4 w/ASCA, Orbx Global series, Ray Smith AFCADS, Radar Contact 4.3, Super Traffic board, Ultimate traffic Live, FS  Real Time, Navigraph Ultimate with simlink, and planning flights with PFPX with Tomcat. 

If anyone flies PMDG planes and hates OOM's then it is totally worth the cost to buy P3D and re buy PMDG products, because you will finally be able to utilize the long haul, study level planes to major hubs all day and night for days at a time. Of course it helps to have a state-of-the-art & well tuned PC. 

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1 hour ago, FSXCYYZEGLL said:

32 Bit means it can access all the way to 4GB, which is what many people report OOMs occurring at, my question is why is the OOM occurring at 3GB of Vas, I know the 4GB limit. Im just confused as to why it is OOMing at 3GB when it still has plenty to access even for a 32bit program.

to answer your question more specifically.. one reason those numbers can be misleading is that they are a sum of all the available free memory, but not necessarily all of the contiguous free memory that is available.

say for example that perhaps the sim is requesting a very large allocation of 256 megs. you may have 1gig free but if it is broken up into a dozen chunks that are spread through the 4g. if none of the free spaces are 256meg in size, it can't make the allocation just doing basic memory operations.

i don't really know enough about the inner workings of fsx memory management to say for sure that this could be a common mishap..presumably it does some garbage collection from time to time (i notice a big hitch/pause upon reaching dense scenery areas..) but maybe not, it certainly does seem to have some mystery about what it releases or doesn't, although this is improved in steam version for sure..

my only suggestion is to keep turning your sliders down until you find the sweet spot. i find that with the triple combination of high detail airports, dense urban areas, and the 777/747, it's only possible to reliably fly in and out by turning off auto-gen sparse or off,and leave other slider at normal or dense only. 

cheers,-andy crosby

 

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Well I've turned the global texture resoltution to high instead of very high everything else apart from water is on max, including ultimate traffic 2. In response to the suggestion of P4D, I simply at the moment can't afford a 400 odd dollar upgrade for my simulator.

Signed Jon

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2 hours ago, hughVFR said:

that Windows can page memory out to the hard drive.

Virtual Address Space has nothing to do with RAM or the page file but I agree with your other comments.  A lot of people thought VAS was RAM or the Page File but it's virtual address space provided by Windows, 64 bit versions only.  32-bit versions of Windows only provide 2GB's of VAS but you can expand that to 3GB's with the 3GB switch.

Best regards,

Jim

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1 hour ago, FSXCYYZEGLL said:

Well I've turned the global texture resoltution to high instead of very high everything else apart from water is on max, including ultimate traffic 2.

If you're not using DX10 Preview (with Steve's DX10 fixer) then you should try that--DX9 uses a lot of VAS with copies of video buffer data, rather than offloading it to the GPU.  But sliders to the right on nearly everything is a predictable textbook recipe for the kinds of problems you're having.  Also, the stock Toronto area has some heavy-hitting scenery objects that get in the way of a number of other add-ons.  And multiple layers of high-def clouds and/or heavy levels of AI traffic from something like a 100% setting in UT2 will clobber VAS as well.

Other than DX10, the advice is pretty standard--start working the sliders back to the left until you get things stable.  Consider 512-bit clouds in AS/ASCA, and no more than 3 layers.  Dial back the traffic in UT2 to 40% or less.  Reduce your LOD radius and autogen levels.  Without complex add-on scenery, you should be able to keep some (not all) of these settings higher than average and make it work.  But stable with everything on max?  Sorry, but FSX hasn't worked set up that way since it first appeared in 2006.

Regards

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The AVSIM FSX Configuration Guide provides good advice too!

Best regards,

Jim

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I could understand pulling the settings back if the VAS had approached the 4GB limit(I will do that with some settings anyways to give it a try like scenery radius), but I still don't understand how you can get a an OOM without the memory approaching the VAS limit of 4GB.

 

Jon

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14 hours ago, FSXCYYZEGLL said:

but I still don't understand how you can get a an OOM without the memory approaching the VAS limit of 4GB.

If you monitor your VAS during a flight using the FSUIPC utility as described in the AVSIM CTD Guide, you can see your VAS fluctuating constantly.  On approach it will go down to maybe 200MB's then shoot back up to over 1GB, then suddenly back down to 400MB's.  If you have high settings and using commercial eye-candy scenery, and lots of Autogen, you will be lucky to touchdown and may not even be able to taxi if you do land.  It all depends on the scenario, your views, the weather, the number of AI in the area, and then the settings.  There is no solution.  FSX is an old program that is not optimized to work well with current OS's but still does a pretty good job most of the time.  The eye-candy at airports and some photoscenery and Autogen are not VAS friendly.  They tend to use the space fairly fast.

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21 hours ago, Jim Young said:

he AVSIM FSX Configuration Guide provides good advice too!

+1

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