RealDCSpilot

@f4l0 Thanks! That was fast. Tested all variants and it works now.

+1 This is simply the best analogy i've read on that matter. A complete other point is, if you are paying FB for the HMD itself any money, you are a fool. It's like paying a vampire's dentist to make sure he can put his teeth into you, the best way possible to drink your blood. They claim that it is subsidized, that they loose money selling it at this "low" pricing. The truth is, they will earn multiple times the money over the years from the data you will provide. If you are really willing to do that, the HMD should be free. Look at their revenue just for the 2nd quarter of this year: https://www.statista.com/statistics/422035/facebooks-quarterly-global-revenue/ It's crazy how much money the business with personal data is able to generate and you are paying on top of it to put a parasite on your forehead.

@f4l0 The new stable version 2.1.0 still triggers a script error for the new variants of the P-47D (30 late and early version, new 40 version with new rocket pods).

Before we start banging our heads against the walls... @Pikey You already were in the zone for the problem in your video at 6:41 in your mission. At this point, when the sudden framedrop occurs, the chances are high SteamVR can fail. It's kind of a precursor for the crash. Usually, in the same situation, an action like switching to the F-14 on the super carrier and using F10 map after that triggers it.

@Pikey Hi mum, try to ... ;) Use the ingame settings i posted under 1.a) set all on "high". Choose maybe 170% SS in Steam VR - it's all about provoking the issue. Just look for a multiplayer server with almost all modules included. It's not depending on a specific mission! Public Training servers hosting the Syria map, like from "Havoc", "Kirk's Hangar" just to name a few. They all have a certain amount of ground vehicle activity, all modules available including the supercarrier plus tankers and AWACS in the air. If the framerate starts to drop like in the 6th minute of your video, you are almost there. One of the next attempts to switch to another aircraft or the F10 map might trigger SteamVR (and it's WMR plugin) to fail again.

For me it's running the game at 2x 2880x3200 pixels, 4x MSAA and extreme visibility range. Looks fantastic and no doubt this will work great on any future VR HMD with higher resolution panels than the current gen.

I can't trigger this issue anymore because my GPU now has 24GB VRAM. I already had 64GB RAM before i upgraded from a 2080ti with 11GB VRAM. So VRAM needs to be watched closely, it's the only factor that changed on my end. Steps to reproduce were: 1. a) use high settings that demand more VRAM (textures high, terrain textures high, water high, vibility range high, heatblur low or high ...) b) raise SteamVR render resolution between 150%-200%, ingame PD setting at 1.0 at all times (somewhere is the sweetspot for your system, restart is always required to apply changes) c) having a bunch of other windows open will also help slightly raising VRAM usage (discord, simshaker ...) 2. choose a server with a big mission like TTI on Syria 3. choose any aircraft, jump to cockpit, choose next aircraft (F/A-18 or F-14 on supercarrier to have the biggest impact), jump into cockpit, check external views, switch to F10 map, switch back to cockpit, switch to F4 external view of other aircraft a couple of times. 4. repeat step 3 and at some point SteamVR should crash. The more different modules you own/can to jump into, the better...

@VirusAM I have a Valve Index and had a 2080ti before, had the sudden frame drop issue and occasional SteamVR crashes over the last couple of patches since the introduction of the Syria map. But i was also always driving the limits of highest possible visual quality settings the whole time and knew that will cause issues. DCS isn't a normal game however, most games are designed to fit in a certain spec range of hardware. DCS just uses everything it get's, the need for 32GB of RAM for instance is quite unusual. But on the other hand, it wasn't designed for highend VR in the first place.

@Pikey Good video with lot's of important information. The only thing that's missing are your exact system specs and DCS settings. What i can clearly see before the 6th minute, your system resources are about to collapse. Your VRAM (8GB) and RAM (32GB) usage is maxed out already, all it needed was to switch back to the cockpit and that was the last drop. Your HD started to try to swap memory from the pagefile back and forth, trying to manage the overflow of RAM and VRAM simultaneously, because there isn't enough memory left in RAM and VRAM. It starts to bite it's tail here, VRAM is full - the system wants to use RAM for sharing video memory, but RAM is already full and starts to make more use of the pagefile on disk. Every I/O is at full load and starts to chase another problem. In certain cases, Steam VR's own part of allocated VRAM seems to fail there, because no resources are left. Edit: ok, just watched more of the video and saw the ingame settings... They are already pretty low. If you would go higher, you should be able to trigger the problem earlier. Atm, only more RAM and VRAM seems to help there.

@FoxTwo Try these settings to push over your VRAM limit. This is basically the highest visual quality for VR that you can achieve with a crowbar and the 3090 just eats it without complaining. It's 18.4m pixels with max settings on nearly everything. https://forums.eagle.ru/showpost.php?p=4524203&postcount=57

@Taz1004 Read again, don't twist what i wrote. I was measuring the whole windows desktop taking 1.4GB VRAM on a ultrawide monitor. Every new window aka "running app" on the desktop, takes a bit more VRAM for the Desktop's screenbuffer. That's how Windows GUI works. Every new opened window needs VRAM to get it's content displayed, because it's a 2D plane with graphical elements which need pixels to be drawn and stored somewhere. It doesn't cost "performance" but it needs resources like VRAM. The more windows aka "apps" are open the less VRAM is left for the game. It's a couple of hundred MB per window on a high resolution monitor. The need for a bigger rendered frame to counter lens distortion is common VR technology for every headset:

Don't forget that this is running more than 4K resolution for each eye. Given that, it's a pretty normal VRAM usage. Running the game on just one 4K display should be a bit under 10/11GB in all situations.

https://www.bradford.ac.uk/t4-ssis/ruski-files/academic-voice/page_07.htm Please provide evidence then. Real information how stuff works and how it matches your posts.

Yeah, like you tried to explain to me in another thread, that Windows, mirroring a screen directly from the front-buffer of the GPU to a second monitor is exactly the same like the extra VR mirror window on the desktop while having VR running. And that this extra window doesn't need extra VRAM to be rendered on the desktop. (Well it does, because it's copied from the VR screen buffer and stored in the front-buffer for the monitor, of course this takes extra space in VRAM. If more windows are open, the more information needs to be stored in the front-buffer)

Goodness... 1. Reverb owners have to use the Windows Mixed Reality plugin for SteamVR. The plugin handles all the necessary api requests first before Steam VR handles the rest. A reverb user will only see the end result, that's why it shows their native resolution at 100% in Steam VR. 2. There is always the need to postprocess lens distortion for a flat frame from a game camera for any kind of VR HMD. Therefore you always need more pixels in a rectangular frame that will be lost during this operation because of the lens matched distortion. This is a basic VR process to display a flat picture on a flat panel that is only being watched through convex lesnes. 3. The PD value in DCS acts as an override in combination with SteamVR. The openVR api asks the game to render a given resolution, but DCS returns a much higher resolution frame if the PD value is higher than 1.0. This is wasting frametime, because it obviously won't fit and needs to be resampled. Letting SteamVR managing resolution and supersampling instead is the much more efficient way. It also has an extra option of an advanced supersample filter under Video Settings. Why don't you test this for yourself? Try to set a PD of 0.5 in DCS and look what happens. The result will be a super blocky low res image, but still supersampled to a high resolution frame with your settings in SteamVR 100% 150% whatsoever... The difference might be if DCS is using the oculus api, here the PD value seems to hook directly into it. I can't test this here. SteamVR and it's openVR api is a image/pixel processing engine. The word "render" can be widely interpreted here. Just a simplified explanation from the api documentation: "One real-world example of an application is a game engine like Unity. Unity calls OpenVR API to get the position and orientation of any attached VR headset and apply them to the Main Camera. Unity then sends the camera image to OpenVR. OpenVR does some operations on the image and then displays it to the real headset screen." Call it what you want...

Don't forget all the other hardware involved. Makes more than 6000 or 7000 quids for the highend experience? :pilotfly: No need for exaggerations if there is enough money to throw at the problems. ;)

@FoxTwo Yes, DCS needs a better memory management algorithm. Something to clean up unneeded resources fast and effective. Then, lesser hardware specs would be enough for the same result.

On my end it affects everything, a good ingame situation for calibrating IPD is standing on the catapult of the super carrier in a F-18 or F-14 and watch the deckcrew running around your plane. If they look like children or giant NBA players, your IPD is off.

It's not "equal", if you use ingame PD you force DCS to render a higher resolution frame on it's main CPU thread. We all know that this is DCS's weak spot for a long time. By shifting the SS workload to the VR compositor, which is running as a separate process on a separate CPU core and thread plus it's own separate GPU pass, you reach a much better balance for performance on your system. It's a neat workaround for VR and the CPU bottleneck DCS is creating with the current state of it's engine.

The VR compositor needs a higher resolution frame to process predistortion for each lens. This picture explains it really well:

To bring everything together, these are the highend settings for the game (only difference is that i use "extreme" for visibility range now): and this is VRAM usage profiling for these settings on Syria map and TTI MP mission: The 3090 doesn't struggle at any point, giving a nice highend VR experience. Only CPU frametime is left as a limiting factor for FPS.

The 3090 turned DCS in a highend VR experience on my end. VRAM problems gone and everything crystal clear on double panel resolution SS plus 4x MSAA. The last limiting factor is DCS's bad CPU frametime, i hope to see improvements there in the future, after the engine overhaul.

Make sure your IPD setting is right. I have to use the ingame setting to bring everything to a realistic scale. Without everything was too small.

Yep, the needed data swapping for shared video memory on disk and RAM is more of an emergency state than normal operation. Pretty bad for performance.

@eatthis Just make a simple test and you will see. 1. set ingame PD to 1.5 and SteamVR to 100% resolution. Watch your CPU and GPU frametimes in the performance graph. Have taskmanager open to also show GPU usage. Make a screenshot. 2. set ingame PD to 1.0 and Steam VR to 150%. Again, watch your CPU + GPU frametimes and GPU usage. Make another screenshot. The results should be different, please post both screenshots here. Make sure to restart the game each time to apply the changed settings correctly.