VRAM question with Nvidia GPUs

[Mr_sukebe]

Hoping that a few of you might be able to assist with a query that I have.

I've recently replaced my 3080Ti with a 5080, the 5080 having 16GB of VRAM.

Whilst in game, if I open the DCS built in FPS monitoring, one of the lines in the detailed block mentions both reserved and used VRAM.  I don't remember that being there before.

Either way, I have been used to my VRAM all being reserved, and that's still the case with the 5080.
However, I don't remember previously being able to see VRAM actively in use.  What has surprised me is that it's not exceeded 8GB during the last few flights.

Can both 5 series and older NVidia users please comment on what you're seeing in the VRAM actually being used.

In short, I don't understand why I don't seem to have a VRAM issue anymore, despite only increasing the VRAM by 4GB as part of the GPU swap and that really confuses me.  I'm wondering if the move to GDDR7 RAM has made the difference.

[speed-of-heat]

Hey there, as a result of you post i started paying attention to VRAM again, i just flew a single mission , but i was surprised by two things, one VRAM usage was way down, certainly under 8Gb after mission load (there was a spike at about 11Gb when the mission was loading , but the second thing was it was giving up VRAM as well so it wouldn't just keep on rising it would also go down I'm on a 4090.  @BIGNEWY did you make any changes to VRAM management, if so well done if not err I dunno ? 

[BIGNEWY]

13 minutes ago, speed-of-heat said:

Hey there, as a result of you post i started paying attention to VRAM again, i just flew a single mission , but i was surprised by two things, one VRAM usage was way down, certainly under 8Gb after mission load (there was a spike at about 11Gb when the mission was loading , but the second thing was it was giving up VRAM as well so it wouldn't just keep on rising it would also go down I'm on a 4090.  @BIGNEWY did you make any changes to VRAM management, if so well done if not err I dunno ? 

I am not aware of any specific changes. Of course the team are constantly looking for ways to optimise and will continue to.

[Mr_sukebe]

4 hours ago, speed-of-heat said:

Hey there, as a result of you post i started paying attention to VRAM again, i just flew a single mission , but i was surprised by two things, one VRAM usage was way down, certainly under 8Gb after mission load (there was a spike at about 11Gb when the mission was loading , but the second thing was it was giving up VRAM as well so it wouldn't just keep on rising it would also go down I'm on a 4090.  @BIGNEWY did you make any changes to VRAM management, if so well done if not err I dunno ? 

Thanks, not just me taken by surprise.

[Lange_666]

There's a difference in VRAM usage between in game measurement and measured with MSI Afterburner.
The MSI one shows a much higher VRAM usage, sometimes more than 50%.

[Mr_sukebe]

1 hour ago, Lange_666 said:

There's a difference in VRAM usage between in game measurement and measured with MSI Afterburner.
The MSI one shows a much higher VRAM usage, sometimes more than 50%.

Interesting.  I wonder which one is correct?  Maybe neither are.

[speed-of-heat]

given it's a PC and given it's software, they both could be correct , depending on what its looking at

[Hiob]

The "real"* memory usage should be shown in the performance tab in the windows task manager. *reserved that is

....scratch that - I'm not awake yet. You were talking about Video mem of course, sorry.....

 

[Mr_sukebe]

I was out earlier in an F16 over Afghanistan.  VRAM use sub 5GB.

No one else wondering about this?

What did occur was whether ED has reduced actual VRAM usage, meaning that DCS would need to more regularly load and unpack new textures.  Could that be why we might have good FPS, that is not really smooth in delivery?

[Lange_666]

Mmm, F-16 Free Flight Afghanistan (2D).
Res: 2560x1440, overall high to medium settings, FPS capped at 60.

30 seconds into the free flight mission I get this:

VRAM: 10+GB, 2 minutes into the flight and it maxes out at just under 12GB, my VRAM is all used up by then.
RAM: 36GB

Edited Saturday at 07:50 PM by Lange_666

[Mr_sukebe]

Try using in game FPS counter within DCS.  I think it’s Right Cntrl and Pause.  Hit that twice and it displays a more complex summary of what’s going on.  Towards the bottom of that rectangle of data, it now shows not only the VRAM reserved by DCS, but also how much is really being used.

In the mission today, DCS had reserved 15.3GB, but was using under 5GB.  
What I don’t understand is why DCS is not making use of more of reserved VRAM?

Edited Saturday at 08:24 PM by Mr_sukebe

[Lange_666]

10GB at mission start (Free Flight), taking a dip 5-10 secs into the mission to 6.9 GB, then fluctuates between 6.9 and 7.4 GB.
Reserved VRAM 11.3 GB out of 12 GB.

[LucShep]

It depends on the module + map combination, and if you're using it in SP or MP.
And, of course, the higher the quality settings and the resolution (4K or VR, for example) the higher the VRAM guzzling.

Try the F-14A/B, or F-4E Phantom II, or CH-47F Chinook, or AH-64D Apache, or KA-50 Blackshark modules in Afghanistan (any variant), or Iraq, or Kola, or Sinai, or South Atlantic, or Marianas (maybe some other new-ish maps and modules too). 
Then, and more so if in MP, you'll see much bigger VRAM usage.

This is problematic for perception because, f.ex., if it's a newcomer just using the default Caucasus map with the Su-25T or FC3 (now FC4) aircraft in SP, then the VRAM usage isn't too much of a problem (though it certainly could be better). The VRAM concerns will probably not even be realized until later, when acquiring "heavier" modules and maps. 

PS: for VRAM monitoring, I'd suggest either LibreHardwareMonitor or HWInfo, as these separate measurement of VRAM (what's actually in use, and allocated).
 

Edited Monday at 12:49 PM by LucShep

[Mr_sukebe]

Of course it depends on the aircraft and terrain, which is why I mentioned examples above.

Just checked out Afganistan with the Chinook.  Whilst jumping into the cockpit cold and dark, VRAM usage (not reserved) was over 11GB.  It then dropped to sub 7GB whilst airbourne.  That's with High textures for both terrain and the aircraft, and ultra settings on the clouds.

Another point that most certainly DID help was to follow up on a suggestion mentioned by Spud today, i.e. the lower the polling rate on my Logitech mouse.  I vaguely seem to remember doing that back on Windows 10. With the move to Win 11, didn't bother.  Either way, dropped the polling rate to 125 and wow, it really did smooth things out and reduce micro-stutter.

[Qcumber]

I just tried the F-4 take off from Afghanistan in VR. About 11.5 Gb VRAM on the ground. Less in the air.

Slightly off topic but the ground is very poorly optimised. If I look straight ahead I get 72 fps with GPU frametimes about 10 ms. Look left it increases to about 12 ms. Look right and it increases to about 20+ ms. I don't know what is going on but it creates some very weird fluctuations in FPS unless you keep your head very still.