Current state of VR vs SLI?

[Voyager]

So, been testing various settings with the new system, post 4.0.0.1b, and clouds are killing me. Medium clouds I greet good framerates, though the 1% lows are still in the 30s. High clouds knock the averages down into the 60's and lows in the 31 range. Extreme clouds put my average around 26.

 

However, I really can't do cloud fights at anything less than High coulds, and extreme clouds are very nice. Sane seas I can tell, this is a GPU limited thing. I'm not yet ready to get a 2080 ti, but with 1080 ti's coming down in price, I'm wondering is it might be workable to get another card and sli them? 

[Lensman1945]

The current VR hardware doesn't support SLI unfortunately

[chiliwili69]

Last weekend I was also experimenting with the new clouds "extreme" in different level of graphics settings( Balanced, High and Ultra). Surprisingly I was getting quite good fps (60 to 80) with SteamVR SS 120% at the Index and non-combat scenario, much better than I was expecting.

 

In any case, to me the extreme clouds doesn´t look nice either (I really don´t like the IL-2 clouds in general, it is just too far from the real thing. I liked the clouds of ROF)

 

I don´t understand how you can have 26fps average with extreme clouds. You have the same GPU than me.

 

From you settings I have this comments, maybe you can get some gain overall (I really don´t know):

 

Shadows Quality: Medium

Mirrors: Simple (try to put it off)

Distant Landscape Detail 4x (try x2)

Horizon Draw Distance 150km (try 100Km)

Landscape filter: Off

Grass Quality: Normal

Clouds Quality: High

Dynamic Resolution: Full

Anti-aliasing: 2

Gama: 0.9

Full Screen: True (try to switch off this)

Enable VR HDM: True

SSAO: True (try to put it off)

HDR: True (try to put it off)

Sharpen: False

Use 4k Textures: True

Distant Buildings: True (try to put it off)

 

Otherwise you  can  try to use WMR "Motion Reprojection" by modifying the default.vrsettings file, it works quite well on the Reverb when I tried some months ago.

[dburne]

6 hours ago, Voyager said:

So, been testing various settings with the new system, post 4.0.0.1b, and clouds are killing me. Medium clouds I greet good framerates, though the 1% lows are still in the 30s. High clouds knock the averages down into the 60's and lows in the 31 range. Extreme clouds put my average around 26.

 

However, I really can't do cloud fights at anything less than High coulds, and extreme clouds are very nice. Sane seas I can tell, this is a GPU limited thing. I'm not yet ready to get a 2080 ti, but with 1080 ti's coming down in price, I'm wondering is it might be workable to get another card and sli them? 

 

What are your system specs and what VR headset are you using?

[Voyager]

Let me try a re-run of the benchmarks. I discovered with the GPU overclock I had to keep MSI Afterburner running in the background, which keeps riva tuner running in the background, and that interferes with Fraps, so I've had to run the current set of benchmarks using the MSI tool, and some of the results have been very dodgy (1200 fps with a min of 0.8 anyone?) I did, however, really feel a difference with the extreme clouds, so I'm not sure it was just a benchmark artifact. 

 

I may turn off the GPU overclock and re-run the test with stock clocks and FRAPS capturing things to see what it shows. I wonder if the AB and Riva Tuner might be causing an issue in the mix. 

 

The system is a Ryzen 3800X with 64Gb DDR 3600 cas 16 ram and a Geforce GTX 1080 Ti Founders Edition. The headset is an HP Reverb, running at native resolution. 

 

Addendum: I'm surprised that turning SSAO would improve performance? I'd thought that that flag was to allow trimming of things that were occuled or otherwise not visible on screen, or do I have that wrong? 

Edited November 12, 2019 by Voyager

[Voyager]

@chiliwili69Apparently my computer is possessed by gremlins with a sense of humor....

 

Discovered that Steam VR had turned Re-projection on, and pinned my FPS at 30fps. After turning it back off, and running my quick mission again, with Extreme clouds, I now get the following FPS:

11-11-2019, 23:38:34 Il-2.exe benchmark completed, 63794 frames rendered in 1171.375 s
                     Average framerate  :   54.4 FPS
                     Minimum framerate  :   39.3 FPS
                     Maximum framerate  :   90.4 FPS
                     1% low framerate   :   37.0 FPS
                     0.1% low framerate :   22.8 FPS

 

A 1% low of 37 fps and an average of 54 fps with Heavy clouds, on Extreme, and all visibility graphics set to max is quite satisfactory, though apparently I may need to turn is off every time I launch the game. Now i just need to figure out why it sometimes decides it needs all the memory and stops talking to my controllers....

[chiliwili69]

2 hours ago, Voyager said:

Steam VR had turned Re-projection on

 

The term "reprojection" means different things in different applications.

 

The Re-projection term used in SteamVR is a kind of Oculus ATW (no ASW) and it is always on. I thought it can not be turned off.

 

Then, the Microsoft guys, used the word "reprojection" to coin the name "Motion Reprojection", which is the "equivalent" Oculus ASW technology which produce intermetdiate synthetic  frames. This is the one I was referring in my previous post.

[Voyager]

@chiliwili69 What I found was, in the Steam VR Application Specific settings, there is a Use Legacy Projection setting to turn off part of ASW, and apparently if you click on the Desktop VR mirror window and press Shift-A it schools disable all f the reprojection and smoothing features: https://steamcommunity.com/app/250820/discussions/0/1732090362042833245/

 

Doing both of those seemed to fix the frame rate cap I had. 

[mpdugas]

On 11/11/2019 at 1:42 PM, Lensman1945 said:

The current VR hardware doesn't support SLI unfortunately

 

Well, there's conventional SLI/Crossfire, (Nvidia/AMD) which all of the IL-2 titles support.  It allows two GPU to work together to produce the final image shown on a monitor.  It generally produces fps increases in the order of 25% or so, but certainly not double what one good GPU can produce.  All VR HMD use the video subsystem's output to create the images on their HMD screens, so if SLI/Crossfire improves monitor imagery by increasing output fps, which just goes to the monitor like the output of a single GPU, then it should also do so in an HMD.  Therefore, conventional SLI/Crossfire should speed up the VR HMD display.

 

However, there is another technology that assigns each GPU of a pair of GPUs to one of the HMD screens.  It's called LiquidVR (by AMD) or VRWorks, if by Nvidia.  It uses one GPU to drive one HMD screen, and the other to drive the second HMD screen.  Currently, the GBS graphics engine is not written to support either of those technologies, but the API is free for the developers to use.  All VR headsets support the output from these technologies.

 

In my VR setup, no GPU card is connected directly to the HMD.

 

I'm in the process of building a system for SLI which I believe will benefit my VR experience.  Eventually, if the VRWorks gets implemented, then my VR HMD will benefit from that, too.

 

I do not know, however, how SLI/Crossfire and the VR twin-GPU technologies work together: VRWorks does not require a bridge to connect the two GPUs like SLI does.

 

See, e.g.

 

https://www.vrheads.com/can-i-use-both-graphics-cards-vr

 

and https://developer.nvidia.com/vrworks/graphics/vrsli

 

and https://devblogs.nvidia.com/vr-sli-accelerating-opengl-virtual-reality-multi-gpu-rendering/

 

for a good read on these technologies.