VR and my VRam Observations.

[The_Nephilim]

Hey guys,

 

I was gonna make up a big write up of all the settings and what they do and how much cycles each took up. but since I am in the middle of a move I will just start with the VRam observations.

 

Sorry no screenshots but I did see clearly what was going on with the first two settings in the options menu.

 

Textures and Terrain Textures.

 

Now I set all my settings to their lowest setting and ran the T-51 Take of from Batumi Hot start as a base line.

With Textures on LOW, my FPS I was getting was 42FPS and the VRam usage was 4.0GB. I then tried the Medium Texture setting and I was getting 41-42 FPS and vRam usage was 4.5GB. now I set it on High and was getting 40-41 FPS and Vram usage jumped to 5.8.

 

OK now lets see what it does with another module so I tried what I think is the worst module as far as performance hog that I have was the Apache.

 

So again VRam usage as follows:   LOW Textures 4.9GB...... Medium 5.7GB and High setting a wopping 8GB Vram usage.. OK now there is quite the variance on each module and from what I was gathering it was module and Setting dependent.

 

And the other thing with the settings is on LOW any writing on the panels in the T51 were blurry and I could not read them. the gauges looked fine just the print on the HUD was blurry.   So I tried Medium and the print was readable and I could easily make out what it said that whilst on a Low setting was blurry and I was still in a good space with my VRam usage @4.5GB. Now at the high setting it might have been a tad more clearer but barely noticable except for the fact it used alot more vRam for little to no gain in either performance or looks..

 

So I would say if you have a GPU with ONLY 8GB you need to be a little stingy with this setting as to not go over in VRam which was at the High setting 5.8GB but remeber all the other settings were Zeroed out and on their lowest setting. so I could easily  use up the remaining 2 or so GB or Vram with some other settings that were vRam dependent like Terrain Textures..

 

And in the Apache I easily maxed out my vRam and things got to stutter real quick.. so my observation is if you have a 8GB Vram GPU keep this setting on Medium..

 

Now I was messing with the Terrian Textures which has a setting of Low and High. Whilst I tried to see the differenece it was ever so slight in the maps I tested Syria and Caucasus. Now with this setting I noticed a slight bump to the Vram usage like .2 points. on Low I got 3.4GB and on High it was 3.6GB. So if you want to save a little Vram and there is not much of a difference from what I saw leave it on low..

 

I stopped there but I would imagine if I tried the apache again in Syria it probally would have been much higher so it needs further testing for usage and difference in settings. 

 

I got my VRam usage from Open XR Tool kit the latest version which had this setting amongst other new settings..

 

What we can conclude with DCS as I am sure someone else has probally had this observation it takes a little bit of patience and testing to determine the total usage of Vram and such. I know if I put that setting on High and go into a MP server like 80's cold war  server that Vram with the Textures on High hit 8.4GB Easily and that was with all my other settings where I had them at.

Now the good thing about the settings is if you dont know what piece of hardware it will effect hold the mouse cursor over said setting and a ballon notification shows up and gives a little bit more info about each setting..

 

Nowing that and experience in Options menu setting from experience you casn find a happy medium or just cut to the bleeding edge of available hardware usage and such.  

 

So if you are just buying a new vid card perhaps 24GB and 16GB Vram users need not be too concerned about setting everything on High you will need to do some testing especially if you are in VR and have 8GB Vram on your GPU or even less. but 6GB VRTam would proablly be minimum..

 

I dont have much more to add and I hope this was a bit informative and helpfull. If you have any question Please feel free to tell me your concerns or questions..

 

 

Edited November 24, 2022 by The_Nephilim

[edmuss]

Another issue on the VRAM front is memory bandwidth, this is comprised of the VRAM speed and the bus width in bits.

Whilst 8gb is actually plenty to fly DCS in VR (it isn't too bad at handling it's VRAM, particularly now @mbucchia fixed the reprojection tanking bug with the toolkit) those cards with the lower amounts tend to also have lower bandwidth. This results in an overall GPU slowdown because it's waiting for the textures to copy.

The 3070 has 8gb 14gbps VRAM with a 256bit bus and 448GB/s bandwidth.

The 3080ti has 12gb 19gbps VRAM with a 384bit bus and 912GB/S bandwidth.

The 3070 will run high textures all day long as but it will get to saturation much faster and start to slow down.

The 4080 actually has only has a 256bit bus but the VRAM is running at 22gbps, resulting bandwidth is 716GB/S which is less than the 3080ti. In theory in DCS vr where there is a huge amount of memory bandwidth required it may actually be slower at the very high resolution, high memory usage scenarios!

Edited November 24, 2022 by edmuss