Poor VR performance, is it just me?

I'm getting really bad framerates with this mission in VR, despite using minimum settings and I'd like to know if it's just me (i.e. something is wrong with my setup).

The .miz is available here: https://drive.google.com/uc?authuser=0&id=14ITQzG7NY12Z24VEPwWrb0pnt2QWOVxV&export=download

My VR performance in general is fine, but this mission seems to cause DCS to really struggle in both 2.5 and 1.5 as soon as I spawn in. I'd be really grateful if another VR user could try it out and see how it performs for them. It doesn't require any particular modules as I modified it so it's for the Su-25T on caucasus.

What I find is that I get great FPS when paused, but as soon as I unpause it the FPS goes through the floor. Strangely when running it only uses 40% CPU (all 4 cores), 40% GPU, 3.8 Gb System RAM and 5.6 Gb VRAM .. so it shouldn't be stressing the system at all.

Is your V-sync off?

I've been trying to find optimal settings for my system recently, so will reply to your question and waffle on a bit about my findings, perhaps we can get a discussion going - not that I'm trying to hijack your thread ;)

Try the following, as then you'll be doing what I did and we can attempt a comparison:

Keep the HMD on your desk, we do not want its screens to activate.

Start Oculus Home. I'm running version 2.whatever the latest update is.

Start DCS. I'm on OpenBeta 2.5 at latest (not Steam)

Bring up the frame rate counter (ctrl - pause)

Load your mission. Do NOT put on your HMD. On my system when I do this it goes full whack, so is a very good indicator for performance. With your mission sitting on the cockpit unpaused I get around 110 - 120 fps. My CPU is at around 30%, my GPU is at 100%.

As soon as I put the HMD on, Oculus's routines kick in and I get a frame rate drop to 45 fps, with ocassional stutters below that.

In my limited experience, you really want to see 90 fps at all times. On 2.5 I find this very hard to do without bringing down my settings; and there will always be situations (especially on airfields with other aircraft) where it's just not possible. So it's a compromise; my settings are below. I am using PD 1.2, no mirrors. I'm sure most people will consider those to be too low, but I find it's a compromise that works for me. One thing's for sure - deferred shading is a no-no for me. Cockpit shadows are also too much of a hit.

As soon as CPU / GPU gets close to 100%, ASW kicks in and you get 45 fps; at this point of course your CPU and GPU have a lot less work to do which is probably why you're seeing those low percentages. I suspect you're JUST pushing your system to its limits with this mission. Then again it does seem odd, since as far as I can tell I can't see anything obvious to tax the GPU. I'm just sat in the cockpit.

Some have suggested disabling ASW through an external tool (Oculus tray tool). However, my experience doing that is not good, as I then get constantly fluctuating frame rates, which I find rather uncomfortable. I just accept that ASW will kick in sometimes, it's not ideal - but it's the best option, imo.

For my own testing I've been using the A-10C mission "Free flight over Black Sea region. Runway start.". No particular reason, just landed on that one by chance. Following the same procedure for that mission I also get around 110 fps (HMD off), however when I put the HMD on, I sustain 90 fps and my CPU and GPU are both around 60%. This would suggest to me that there is something peculiar about your mission.

BTW, when I close the mission, I get a script error. No idea if that has anything to do with it.

edit: I don't look at all cores, as I believe that is an average. My cpu % relate to the most heavily utilised core, which I think is what you should be looking at.

Hey I was really wanting to ask a question about VR but didn’t want to start a new thread for it - I hope you won’t mind me asking here.

What VR headset is it you are using? Does DCS only support the Oculus atm?

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Thanks Hippo, that's really helpful!. Turns out the answer is "Deferred shading" I'd never thought of turning it off (since it's turned on by default by the "VR" setting, and I didn't actually know what it did). But yes, it absolutely kills the framerate something chronic.

I can't get framerates as good as yours, in that test I get around 60FPS with deferred shading off. If I turn on deferred shading then it struggles to hold 30 FPS. The rest of my graphics settings are slightly lower than yours, which is interesting because as you can see from my sig, my CPU is less powerful than yours but my GFX card is a bit better. Seems DCS is very CPU heavy, I see a CPU upgrade in my future :)

Again big thanks, I'd never have worked out "deferred shading" was such a problem.

Incidentally the script error is nothing big, it's just the script to generate the next mission of the campaign. This mission was generated by the MBot dynamic campaign engine.

Also make sure your select full screen in the settings. This way nothing other than the HMD screen mirror of the left eye is being drawn on your monitor. I've noticed s significant increase in FPS in all of my games. You may have to do a Alt+Tab and Alt+Enter from the desktop to make sure that DCS is the focus.

No problem.

Deferred shading is a setting that has a major impact on how DCS looks and performs, you may want to check out:

https://forums.eagle.ru/showthread.php?t=205841

and

I also would have thought that with your 1080 you should be getting higher frame rates than me.

Are you still referring only to your mission or to any? What frame rates do you get if you try the mission I suggest (I'm assuming you own the A-10C)?

I doubt it is down to your CPU. When you did the test (HMD not active), were any of your cores hitting 100%? If not, then I expect the GPU probably was, and if so, it wouldn't be a CPU bottleneck. If neither were at 100% then (a) your system isn't behaving like mine or (b) something else is limiting your system's performance.

At this point, I'd guess something's not right. I assume you've done all the usual - latest drivers, etc.

I'm a VIVE user and have just fixed a lot of jitter issues by getting rid of Oculus Home and Revive off my system.

I've been doing a lot of tinkering today so can't be absolutely certain it was THE fix but worth a shot to any other vive users that have the oculus software installed and are having jitter issues in 2.5 too.

Spec:

Ryzen 5 1600 @stock, RX580 8GB , 16GB Ram , SSD

I'll try the mission tomorrow. However, I use the Rift and fly online pretty much exclusively and my frame rates will stay at 45 because of ASW. But my settings are DS on, MSAA off, all shadows flat, PD 1.8, trees 80%, preload 100,000, all other settings high except civilian traffic which is off, chimney smoke off, cockpit res 1024, cockpit global lighting off, full screen on and grass clutter off.

It's absolutely gorgeous and I don't get frame rates below 45 and it's smooth as silk. Two of my friends have plain 1080's and they run the same settings with no issues and one is running your processor. If you ask me it has to be something in the mission. Flying on the 107th there is a shit ton of objects to be processed. Processor speed is the one PC component that DCS doesn't seem to hog but you want the most amount of memory you can get and the fastest SSD. Also, if you have an SSD change your windows page file to the amount of memory you have on board.

It was slow because you had MSAA AND Deferred Shading on, they don't play well together at all - turn MSAA off and turn Deferred Shading back on, it'll look a lot better.

I didn't realize this, but change the resolution to 1024x768. I noticed it on others that were claiming awesome performance. Made a world of difference and doesn't impact the headset resolution.

Are you sure on that one? The resolution is for the monitor only when not using the Rift. What you see on the screen when using the Rift is the left eye view being mirrored. In other words it's really not taking any resources. I originally thought having three screens selected made it look better but I'm pretty sure it was a placebo effect but you got me interested in checking it out again.