Interesting Performance Find (VAS and FPS)

[DAL1850 51]

I had no wish to offend you. Think you may have misunderstood. I just interpreted your post as something you had discovered and were offering to the community. No criticism or snobbery intended.

 

No worries, mate. My remarks were addressed to others.

[DAL1850 51]

Sometimes a picture is worth a thousand words.

Here's a photo comparison of two LOD levels (4.5 vs 8.5) with a view of Marble Canyon, AZ. You'll see that at ground level, the difference is almost imperceptible (it's there though if you look near the horizon). However, at altitude (this shot taken at 10K), the terrain textures from about the lower third of the frame and above are markedly sharper. If you fly with a lot of haze or cloud cover, you may not ever notice the effect below 10,000 feet.

Ground w/ Default LOD
http://btfy.me/x3t8bc

Ground w/ High LOD
http://btfy.me/cw638r

10K Spot w/ Default LOD
http://btfy.me/xwbvhd

10K Spot w/ High LOD
http://btfy.me/dv4f3p

It's probably easiest if you open each of these images in a separate tab in your browser and just click back and forth between them to see the differences.

 

PS. I chose 8.5 for illustration purposes only. I highly recommend you DO NOT run with an LOD_RADIUS of 8.5 unless you're content to fly the stock Cessna or the sailplane My VAS was at a whopping 2.7GB here; I doubt the T7 could even load itself! 6.5 seems to be a very happy middle ground with pleasing visuals that won't blow the lid off VAS (especially with realistic sky/visibility haze in place which these photos do not have).

[777simmer 117]

Yes nice pics and and you can clearly tell the difference.

[Fatback 84]

Great pics. You're right, a picture is worth a thousand words. Someday we'll have a 64 bit Flight Simulator and we'll be able to do that!!!!

[777simmer 117]

So about VAS:

 

I downloaded the Process Explorer today, to see where I am VAS wise.

Never had an OOM by the way!

Just curious.

 

Note:

For the first time since a few weeks I also changed back from non clocked to my 4.4Ghz overclock!

 

To see the VAS window I had to change from full screen mode to windowed mode in FSX.

 

KJFK 31L departure, heading straight out over Manhattan X and UTX USA.

Fair weather.

Scenery sliders for comlexity and autogen at Dense (as always) which is two nodges down from max I think.

AI traffic at 11%

Not required scenery deselected in the library.

 

Looked at VAS, and what do you know.....3.7GB VAS in use by FSX and increasing.

Then a ding dong in the background.....a VAS alarm?

Is there such a thing?

Then OOM and by by FSX :-(

 

I say again; I have never had an OOM in my life!!!

 

Note:

Changed my overclock back to normal, so not overclocked!

 

Tested a bit more and it seems Windowed mode is the problem.

In Windowed mode I had 3.5GB VAS in use this time (that is a bit less then before when I was still running overclocked, but could just be due to the restart of the PC)

When I switch to full screen, and looked at VAS usage right before the sim changes to full screen, it dropped from 3.5 to 2.7GB!!!

 

You guys have that as well?

[Fatback 84]

Hey Rob, the ding dong is the FSUIPC low VAS warning.

 

Interesting that you had lower VAS in full screen. I'm in the middle of a flight now, and I always fly windowed mode because I have other apps running on a second screen. So I started up Process Explorer and my VAS was at 2.2GB. I alt entered into full screen mode and then waited a few seconds to ctrl escape and bring up the task list and then Process Explorer again and it was at 2GB. Not a very scientific test but that's over a 10% difference. So instead of being at 4GB and OOMing I'd be at 3.6GB and cruising happily along. I wonder if this is consistent. If so you've made a huge discovery!!!

[DAL1850 51]

I think what you're observing is an effect of the Direct3D device being reset as you switch between fullscreen and desktop. Whenever you do this, Direct3D has to purge all of its state and texture memory, reinitialize and load them back in again (that's why you get that longish pause when toggling between modes). Since there is texture caching going on behind the scenes, I suspect that when you reset the Direct3D device like that, you observe a momentary drop in memory usage as those cached textures are freed from RAM. It takes time for those caches to refill. To really test this theory, you would need to fly around for a period of time and compare (fly for 10 minutes in a scenery area in windowed mode...then switch to fullscreen and fly around for 10 minutes and compare your VAS). I suspect they will eventually settle out to about the same.

[777simmer 117]

And I wanted to that except that each time I return from full screen to windowed mode my Process Explorer has crashed :-(

 

Whats up with that??

[Fatback 84]

I don't have a lot of OOM's but when I do they're landing when the arrival airport starts using up memory as I approach it. If switching to or from full screen to windowed mode clears up some cache and frees up some VAS that would be enough for me to land and finish the flight. Worth experimenting...

[777simmer 117]

Still have Process explorer crashing all the time.

 

But it seems I am using less VAS now that I not overclocked.

About 300 - 400 MB less.

No more OOMs now.

Have to do some more experimenting to be sure.

 

Does that make any sence to anyone?

[Christopher Low 5,335]

Nothing about FSX makes any sense.

[777simmer 117]

Nothing about FSX makes any sense.

lol, thats true

Anyway, my overclock seems not to matter.

 

Back at 4.4Ghz and its the same as not overclocked.

Very close to the VAS limit.

 

To stay under those 4GB I have now added:

[bUFFERPOOLS]

UsePools=1

Poolsize=8388608

RejectThreshold=262144

 

Seems to keep my VAS under 3.6GB (quite a bit better than OOMs).

All was tested over the Manhattan X area.

[Fatback 84]

Why would Bufferpool settings affect VAS?

[777simmer 117]

Why would Bufferpool settings affect VAS?

I have no idea, why should it not?

[Fatback 84]

I don't know that either. But VAS is such a big problem that understanding it might be beneficial.