FSX-MS Word of Caution if coming or going to Guam in FSX

[chad556 1]

For the past week, I have been pulling my hair out trying to figure out why Can t land at PGUM without getting the dreaded OOM error then crash. Turns out the freeware scenery on Avsim and Flightsim.com is crap. Its called Guam X V2 by Morten Linde. The scenery looks beautiful, if it worked. Upon loading ANY aircraft onto the airport, the scenery immediate gobbles up at least 3.9gb of VAS memory. Those of you who have done the research on VAS memory in FSX and OOM errors know that this scenario is a no-go. I cant believe the guy released it without doing a few tests for memory leaks, etc. The ILS frequencies are also incorrect. 

 

With that said, I challenge any of you to load up at PGUM in the PMDG 737NGX using the freeware scenery named Guam X V2 by Morten. Keep in mind, I have HD textures disabled completely in my sim, and in the NGX. My LOD radius is 4.5 and I have NO buffer pools at this time.

[1st fltsimguy 466]

Wow, I just checked your PC specs, given the powerhouse of computer you are running that is amazing.

 

Interesting, while I have not tried that scenery, in all my years with a heavily loaded FSX, I have never had an OOM error.  Lucky me.

[honanhal 1,420]

Yeah, unfortunately that scenery just doesn't work. It will OOM in the default trike!

 

Seems amazing that the designer didn't test it at all, apparently.

[chad556 1]

Thanks Honahal. Its a bit reassuring hearing it's not just an issue on my end. 

[ShawnG 1,823]

I can't comment one way or another on the scenery, since I don't have it.  but your specs say you have 4 gb of video memory,  which in dx9 is mirrored in VAS,  so if you load that up, you are losing headroom in VAS.  are you using dx9 or dx10?

[chad556 1]

I can't comment one way or another on the scenery, since I don't have it.  but your specs say you have 4 gb of video memory,  which in dx9 is mirrored in VAS,  so if you load that up, you are losing headroom in VAS.  are you using dx9 or dx10?

Using dx9. It really shouldn't matter though, FSX is only capable of handling 4gb of VAS due to its 32 bit platform. 

[ShawnG 1,823]

yes,  but the difference is that dx9 mandates that whatever you have in video memory be mirrored in VAS,  not such a big deal with a 1 gb card,  but your monster 4 gb card could theoretically take out your entire VAS space if it's using all it's memory (which it might be if this scenery isn't optimized)  dx10 doesn't mirror anything into VAS, so you have a lot more headroom to play with.  somebody with a lesser video card might not be seeing this problem.  I'll see if I can download and test it sometime tomorrow,  this has me curious.

[chad556 1]

yes,  but the difference is that dx9 mandates that whatever you have in video memory be mirrored in VAS,  not such a big deal with a 1 gb card,  but your monster 4 gb card could theoretically take out your entire VAS space if it's using all it's memory (which it might be if this scenery isn't optimized)  dx10 doesn't mirror anything into VAS, so you have a lot more headroom to play with.  somebody with a lesser video card might not be seeing this problem.  I'll see if I can download and test it sometime tomorrow,  this has me curious.

 

Wow, that makes a lot sense actually. Thanks for taking the time to explain that. Please report back with your findings. BTW I'm using a GTX 690 card. I know the critics dont recommend using a massive dual GPU card like this for FSX, but I need it for other applications. Looking forward to your results. 

[mikea76 184]

Interested in this as well. . I am using a 4 GB video card...  

[simmerhead 885]

If it doesn't work I'm sure you can get a refund from the developer

[Don t moderate me this way 882]

So, with a 4 GB video card and using DX9, I will OOM anywhere/anytime? That's actually hard to believe ...

 

BTW, anyone measured VAS with the Aerosoft payware 'African Airstrip Adventures'? I was puzzled by the fact, that you can OOM there even in a GA plane(!) if your settings are too high?!? (Pls. note there's no huge highly-detailled airport in the scenery area.)

[NikkiA 7]

It actually works fine for me, well, by fine I mean it doesn't crash, I get ~8fps on the runway, and ~22fps in the air.

 

I notice that the author states that he's reworking it for v3 and removing things that cause the massive fps loss.

[xplanery 250]

So, with a 4 GB video card and using DX9, I will OOM anywhere/anytime? That's actually hard to believe ...

 

I'm using Radeon 6990 which has 4GB of video memory and I don't have problems with OOM while using DX9. 

[ShawnG 1,823]

just because you have a 4 gb card doesn't mean that your card is constantly using 4gb,  in fact,  most of the time, you probably aren't using any more video memory than anyone else,  But if something happens to cause you to use that much,  then it would be OOM city in dx9.  my 2gb card has caused me lots of trouble with different scenery, that's why I switched to dx10.  it's not a simple thing though, that you can make a blanket statement about it,  but it is a possible source of the OP's issues.

[tttocs 301]

yes, but the difference is that dx9 mandates that whatever you have in video memory be mirrored in VAS,

 

This doesn't work the way you seem to think it does.  In the old days of 32 bit systems, where EVERYTHING - every device and card - had to be mapped into a total of 4 GB of addressable space and any video memory used did have to be completely mirrored, large cards like this would've been a disaster - basically impossible.  Now, on a 64 bit system, the card itself lives in it's own address space and doesn't compete with other stuff.  The mirroring only occurs in DX9 when you start to actually use VRAM.  The 4 Meg card's VRAM isn't mirrored back to the application's VAS - it's the other way around - the application keeps a mirror of what it sends to the card, and even then, ever since a patch back in the Vista days (pre-service pack 1 Vista) NOT EVERYTHING has to be mirrored.  This was a fix made for "legacy" DX versions (9 and previous) to help with these kinds of problems.

 

Yes, some mirroring occurs, and DX10/11 is generally better in this regard as it doesn't require mirroring in the application's address space at all, but the DX9 situation isn't quite the disaster typically depicted. If it was, most of us would be OOMing most of the time. :-)

 

Scott

 

Edit:  Ah, I see your clarification posted while I was typing!