Strange VR performance issue

[Glide]

I did a couple of quick passes on this with the GPU monitor open, and it does seem as though stutters cause a jump in Shared GPU memory usage.  I also noted this behavior around the carrier group (did a bolter on the George Washington with my Viper).  More investigation required.

[Glide]

After the Syria testing, I flew a couple of Caucasus tests with terrain textures on HIGH.  I could not get any Shared GPU memory to accumulate on that map.  However, I could get my Dedicated GPU memory usage to go from 9.1 GB to 10.3 GB just by flying over the Super Carrier group.

 

Then I jumped back to Syria and put the Super Carrier group in the bay at Beirut.  I could get 1.1 to 1.7 GB of Shared GPU memory right from takeoff. 

 

I also noticed that the Shared GPU memory does not get flushed between missions. 

 

I'm going to keep an eye on the Shared GPU usage over the weekend. 

[Glide]

Also could not get Persian Gulf to accumulate Shared GPU Memory or stutters with an ordinary ground action/dogfight mission.  Going to try adding a few dozen super carriers to see what that does to Shared CPU mem.

[Glide]

The F-16 Free Flight on Syria is a good one to test if you don't want to build a mission.  I see now why it all looks so rosy when you have 11GB of VRAM and 32GB of RAM.  The game sits at a steady 28 GB of RAM usage and about 11.5 GB of VRAM at 4k with all the goodies turned up high. 

[Glide]

19 hours ago, divinee said:

I have to try that, TY Mustang for the tip!

I managed to backtrack that memory leak a little bit and it seems that if gpu is not using ”shared memory” seen in windows perf tab, all is fine. After shared memory starts to get used like in heavy MP PvE missions or very heavy SP missions, the problem starts.

@divinee you are my hero.  I went back to Caucasus and Persian Gulf, turned on SSAA X2, SSLR, AF 16X, MFAA, and AATR Supersample X2.  My card never ventured into Shared GPU memory, and it was quite simply perfection!  No stutters, good frame rates, and all the eye candy you can want.  Thank you so much! 

[Glide]

I see the pattern emerging now.  If your card is using Shared GPU Memory AND you have SSAA or MSAA enabled, you will take a big performance hit.  If you are using Shared GPU Memory and you have SSAA and MSAA disabled, performance will be ok, but the VRAM leakage seems to occur when the card uses Shared GPU Memory.

 

Unfortunately, this makes it tough for anyone with less than 8GB of VRAM to enjoy Syria.  I had to turn down textures, water, shadows, and visibility to get the VRAM usage on Syria down to below 8GB. 

 

Get your VRAM usage down as low as you can go, and turn off all antialiasing if you can't keep your card from using Shared GPU memory. 

[divinee]

Is that shared memory handled by game or by nvidia and dx? Rolling back drivers doesn’t help so my guess is by the game. @BIGNEWY or @NineLine can maybe inform that if we are up to something? Because if ED is already aware of this problem we are troubleshooting for no reason

 

I installed those drivers from Mustangs post and they seem to make small improvement. Not absolutely sure but feels like that shared memory is clearing better. Can be placebo so we need testing results from another users also.

 

@glide good to be help

[Glide]

It would be very easy to see shared GPU memory cleared if Mustang's driver is working; it will go to down to .1 GB between missions.  I don't know who controls the Shared GPU memory.  I did notice that it gets used even when the Dedicated GPU memory is not full during loading, but it clears out by the time the game is loaded.

Edited January 17, 2021 by glide

[Glide]

Just to give you an idea of how I brought my VRAM usage down, I chose the settings that worked with Syria map because I was sure these would work with PG and Caucasus.

Textures = Medium

Terrain Textures = Low

Shadows = Off

Terrain Object Shadows = Off

Water = Low

This brought Syria down to about 8GB of VRAM, and Textures = Low brought it down more. 

Visibility Range = Extreme

Preload Radius = Max

Clutter/Grass = Max

Trees Visibility = Max

These did not seem to increase VRAM usage.  YMMV.

Persian Gulf Map is lighter than Syria.  Caucasus is the lightest.  I haven't tested the others.

 

If you have the cash and can find inventory, get a card with LOTS of VRAM.  12GB minimun for Syria Map.  There are lots of 24GB cards on the market, but inventory looks ugly for now.  Prices for 24GB Nvidia cards are crazy high. 

Edited January 19, 2021 by glide

[speed-of-heat]

this caused me to look at my own VRAM and RAM utilisation in Syria, VRAM was just over 23Gb allocated, and RAM utilisation was at 90+%

[Glide]

1 hour ago, speed-of-heat said:

this caused me to look at my own VRAM and RAM utilisation in Syria, VRAM was just over 23Gb allocated, and RAM utilisation was at 90+%

That mission must be huge.

[speed-of-heat]

it was the f-14 freeflight mission from memory 

[Glide]

In Task Manager, at the bottom of the Performance tab when you have GPU selected, you will see GPU memory, Dedicated and Shared.  The Dedicated and Shared add up to the GPU Memory.  Mine is sitting at 0.9/27.0 GB meaning 0.9 USED, 27 AVILABLE of which 0.8/11 GB of Dedicated memory is used and 0.1/16 GB of Shared GPU Memory is used.  I am guessing you have an 8GB video card.

Edited January 20, 2021 by glide

[speed-of-heat]

24

[Glide]

How much shared GPU memory do you use?

[speed-of-heat]

almost none 0.2

even with low terrain textures it wants 12.2 in the same mission

Edited January 20, 2021 by speed-of-heat

[Glide]

Makes sense.  I only tested the F-16 and F-5E.  How is your VR performance?

[speed-of-heat]

my settings are in my sig, a lot depends on the scenario etc... but in "general flying" more at 90 than at 45, i only typically get 45 when i start to get CPU bound or when i am super low to the ground the tree density is high , and the only time i get real perf issues are when i am on the deck of the super carrier with shadows 

[Glide]

I saw your main post on your 3090, and thanks for sharing all that.  You are living the dream for VR.  I've got my 2D set up now so I don't have to look at settings again until something bigger than Syria comes out.  I am eyeballing a newer card as soon as there's some stock in the stores.  The Radeon RX 6000 series looks very cost effective, so maybe next cyber monday sale. 

[speed-of-heat]

yep fingers crossed, I know how fortunate I am, though it took a lot of focus to get what i wanted, the sad thing is that there is always "more" I don't really know team RED cards/processor that well so i would be interested to see how it goes

[Glide]

I know! Just when I think it's perfect, it gets more perfect.   It never gets boring.  The future is bright for flight sims and VR.  If you follow the "DCS Press" on Youtube there are more optimizations inbound too. 

[speed-of-heat]

Yep, fingers crossed