VR Advice Needed!

[AhSoul]

I recently got a Quest 3 and am dipping my toes into DCS VR. My specs are

• Intel 12600KF
• 32Gb DDR4 at 3600
• 3080Ti

I'm running MT DCS, Virtual Desktop (it looks nicer to me than link cable, I guess due to the better codec?) and OpenXR, and with DLSS on I'm just about hitting 72FPS in Instant Action missions on Caucasus (I don't want to use ASW). I'm not able to keep it to 72 though if there's a lot going on, smoke etc. Other maps like Syria reduce my FPS, some modules get me better FPS than others too - the Apache for example seems to be a lot more taxing. I'm also getting stuttering even when at my target FPS - if I look forward the ground looks smooth, but if I look to the side the ground seems to 'jump'.

I'd prefer not to use DLSS - it makes everything less clear even with sharpening on - so I'm trying to work out whether I need to upgrade everything or just my GPU so I could stop turn it off and use MSAA instead.

The FPS monitor in DCS seems to suggest I'm CPU bound (main thread?) but then the OpenXR Overlay seems to suggest I keep running out of GPU headroom. So I'm not entirely sure which direction to go in first!

[speed-of-heat]

you could try DLAA  instead... 

[AhSoul]

2 minutes ago, speed-of-heat said:

you could try DLAA  instead... 

Wouldn't that make my framerate worse, given there's no upscaling?

[av8orDave]

I’d guess you’re running out of GPU headroom unless you’re flying really complex missions (which instant action shouldn’t be). Some thoughts to improve frame rates:

- Textures medium, terrain textures low

- Shadows medium

- Water medium

- Clouds low

- Visibility distance medium

- Use DLAA (or DLSS)

- Turn grass and ground clutter down

- Turn forest and scenery detail down

- Upgrade to a 4090

I just made the jump from a Ryzen 9 5950X & 3080 to a Ryzen 9 7950X & 4090. I can now max out almost everything, and keep 72 FPS in even really complex Liberation and Retribution missions.

[Insonia]

Spoiler

The CPU and GPU processing are decoupled and placed side by side inside a buffer. called a queue. But at end, for make it easy to understand consider each frame = CPU frame time + GPU frame time

Diagnose Frame Skips And Stutter In DirectX Applications - int13 (ewirch.github.io)

Reducing both CPU and GPU frame time will help increase your framerate, obviously.

As for which one was "bounded", each programs may use different metrics to compare. Some program simply compares the one has the longest delay.

I'm not clear how DCS determined which shows as "bounded" when VR and vsync are enabled. In VR, when Vsync is set to a longer interval, DCS shows the CPU as bounded, possibly due to the VR driver applying a frame cap. The CPU was forced to wait.

But at the end you want both to be low.

Generally speaking, upgrading the GPU has better performance/per dollar return than upgrading the CPU. But In combat, DCS CPU frame is the one affected the most.

So upgrading your GPU may give you better overall baseline performance; upgrading your CPU and memory is going to help you reduce framerate loss in heavy missions and combats. 

Also consider how inefficient DCS engine was, sometimes you need to consider if it really worth it.

 

VR Performance Upscaling Dilemma:

Uneven frame intervals in VR are the most common cause of motion sickness. As a result, most VR platforms use fixed interval vsync rather than VRR. Most headsets select very few set of intervals. So in VR, every CPU and GPU queue must fit perfectly within the interval:

 

 the "Ideal sync"

However, in virtual reality, the GPU must render each frame twice. The overhead for each frame is around 1.5x to 2x more than your pancake mode.

Sometimes it just doesn't fit in.

gap between queue, frame skips, and stutter happens

VR driver then force your CPU slow down to next lower frame rate speed bumper, so it has bigger size to fit in.

 

Here comes to the Dilemma:

Because VR has a large overhead. For instance, it may need a 100% faster GPU and 70% faster CPU to fit inside each intervals.

And if you pay another $2,000, you will only get a 70% faster GPU and 50% faster CPU. But it is still not quick enough to fit. The VR driver continues to order it to slow down. 
VR has no framerate improvement. Except for input lag, and better temporal stability, reduce a few micro spikes.

Now, an even more powerful system is forced to use the low vsync rate, resulting in reduced CPU and GPU usage indicators in your taskmanager. Which confuses a lot of people. The machine must exceed that threshold, or no FPS improvement except for the temporal stability.

 

Edited January 15, 2024 by Insonia

[AhSoul]

24 minutes ago, davidrbarnette said:

I’d guess you’re running out of GPU headroom unless you’re flying really complex missions (which instant action shouldn’t be). Some thoughts to improve frame rates:

- Textures medium, terrain textures low

- Shadows medium

- Water medium

- Clouds low

- Visibility distance medium

- Use DLAA (or DLSS)

- Turn grass and ground clutter down

- Turn forest and scenery detail down

- Upgrade to a 4090

I just made the jump from a Ryzen 9 5950X & 3080 to a Ryzen 9 7950X & 4090. I can now max out almost everything, and keep 72 FPS in even really complex Liberation and Retribution missions.

I've done most of that (I think I still have the clouds on 'standard') - pretty much changing one at a time to see what makes a difference.

Kinda feels like I've gone as low in terms of detail as I want to get - I don't want to play in VR if it looks <profanity> I guess

Maybe hardware is the only solution - just not sure which thing to change first.

Feels like there's so many variables though....

22 minutes ago, Insonia said:

 the CPU and GPU processing decoupled, but at end consider each frame = CPU frame time + GPU frame time

Diagnose Frame Skips And Stutter In DirectX Applications - int13 (ewirch.github.io)

 

Reducing both CPU and GPU frame time will help increase your framerate, obviously.

As for which one was "bounded", different software may use different metrics to compare. Some software only compares which one has the highest delay. 

Im not sure how DCS chose which shows as "bounded" when VR and vsync enabled. but one for sure when in VR when Vsync was fixed to a bigger interval, DCS always shows CPU as bounded probably due to the frame cap was issued to the CPU by the VR driver. CPU was forced to wait.

 

But at the end you want both to be low.

Generally speaking, upgrading the GPU has better performance/per dollar return than upgrading the CPU. But In combat, DCS CPU frame is the one affected the most.

So upgrading your GPU may give you better overall baseline performance; upgrading your CPU and memory is going to help you reduce framerate loss in heavy missions and combats. 

Also consider how inefficient DCS engine was, sometimes you need to consider if it really worth it.

 

 

Very useful!

Just thought, I don't have vsync on - it's still off from when I was playing on my Gsync monitor. Should I turn it back on again for VR?

Edited January 15, 2024 by AhSoul

[Mordants]

16 minutes ago, AhSoul said:

I've done most of that (I think I still have the clouds on 'standard') - pretty much changing one at a time to see what makes a difference.

Kinda feels like I've gone as low in terms of detail as I want to get - I don't want to play in VR if it looks <profanity> I guess

Maybe hardware is the only solution - just not sure which thing to change first.

Feels like there's so many variables though....

Very useful!

Just thought, I don't have vsync on - it's still off from when I was playing on my Gsync monitor. Should I turn it back on again for VR?

 

Just to add that I never looked back once I got a 4090 last year for my system. The lastest DCS update fixed the freezes and stutering for me.

[AhSoul]

2 minutes ago, Mordants said:

Just to add that I never looked back once I got a 4090 last year for my system. The lastest DCS update fixed the freezes and stutering for me.

I'm wondering about the 4080 Super about to come out. It's like 1/2 the price of the 4090 and I guess can't be thaaaaaat far off in terms of power?

Someone on Reddit suggested I shouldn't use VD but use the link cable. Do we know that the cable is definitely the better option? It looks worse to me when I try it....

[Mordants]

5 minutes ago, AhSoul said:

I'm wondering about the 4080 Super about to come out. It's like 1/2 the price of the 4090 and I guess can't be thaaaaaat far off in terms of power?

Difference I believe is the 24gigs of VRAM

 

[AhSoul]

3 minutes ago, Mordants said:

Difference I believe is the 24gigs of VRAM

 

How much VRAM do we need???

[Mordants]

2 minutes ago, AhSoul said:

How much VRAM do we need???

I'm absolutely no expert but as far as I understand it especially for VR, you can never have enough............lol

 

[Qcumber]

1 hour ago, AhSoul said:

I'm also getting stuttering even when at my target FPS - if I look forward the ground looks smooth, but if I look to the side the ground seems to 'jump'.

Try using 90 Hz and ASW to lock at 45. As long as you stay above 45 FPS it looks smooth. 

[AhSoul]

1 minute ago, Qcumber said:

Try using 90 Hz and ASW to lock at 45. As long as you stay above 45 FPS it looks smooth. 

I tried ASW at 72 (so halved to 36) and got weird artifacts and stuff. I'm sure when I tried VR ages ago with my Quest 2 ASW gave me crazy ghosting e.g. aircraft or buildings to the side of me. Would things be different at 45/90?

[AhSoul]

Also should I use ASW in Oculus Tray Tool or OpenXR?

[AhSoul]

This guy also has a 3080ti, and isn't using DLSS or ASW, and his game seems to be on higher settings than mine with no visible stutter and a solid 72fps. ok his CPU is and i9900 and he has 64Gb of ram though....

[AhSoul]

But he's setting his FOV Multiplier to 0.65, so must be cropping a massive chunk of the view???

[Qcumber]

43 minutes ago, AhSoul said:

I tried ASW at 72 (so halved to 36) and got weird artifacts and stuff. I'm sure when I tried VR ages ago with my Quest 2 ASW gave me crazy ghosting e.g. aircraft or buildings to the side of me. Would things be different at 45/90?

45 FPS ASW will give better results over terrain but you will get ghosting. To be honest, unless you can maintain a steady 72 FPS all the time, you will get some ghosting. I don't think even 4090 users can achieve this. 

 

40 minutes ago, AhSoul said:

Also should I use ASW in Oculus Tray Tool or OpenXR?

I think you are confusing runtime and API. Open XR is the application programming interface. Oculus app is the runtime. OTT lets you edit the oculus debug tool settings more easily. Set ASW with OTT and set some key binds so you can toggle between ASW 45hz forced and off. That's what I do rather than relying on the auto function. 

16 minutes ago, AhSoul said:

But he's setting his FOV Multiplier to 0.65, so must be cropping a massive chunk of the view???

That must look terrible. Try using quad views foveated rendering to reduce the peripheral view to lower res. This will give a big performance boost but still retains a good FOV. 

https://github.com/mbucchia/Quad-Views-Foveated

[AhSoul]

1 minute ago, Qcumber said:

45 FPS ASW will give better results over terrain but you will get ghosting. To be honest, unless you can maintain a steady 72 FPS all the time, you will get some ghosting. I don't think even 4090 users can achieve this. 

 

I think you are confusing runtime and API. Open XR is the application programming interface. Oculus app is the runtime. OTT lets you edit the oculus debug tool settings more easily. Set ASW with OTT and set some key binds so you can toggle between ASW 45hz forced and off. That's what I do rather than relying on the auto function. 

Yeah I'm probably getting confused - so many tools to mess with....

[AhSoul]

Tried with the link cable and ASW 45 (with the headset on 90). Definitely felt smoother, though the graphics looks muddier compared to VD, so I assume I need to play about with the Oculus App and Debug settings.

Weirdly it doesn't seem to be running OpenXR like it does with VD though. I've used the OpenComposite tool to make OpenXR the default, and in the Oculus app it says the Oculus Runtime isn't the default, and Steam VR isn't running, but I don't get the OpenXR overlays. So I assume it's using Oculus?

[diego999]

2 hours ago, AhSoul said:

 

Just thought, I don't have vsync on - it's still off from when I was playing on my Gsync monitor. Should I turn it back on again for VR?

 

 

Vsync is ignored in VR. It only works in 2D mode.

[Qcumber]

35 minutes ago, AhSoul said:

Definitely felt smoother, though the graphics looks muddier compared to VD

I find the opposite with the quest pro. Just make sure you are comparing like for like as I'm not sure the full output from oculus is the same as with VD Godlike. Set the sampling to 1.5 in OTT and see how it looks. Also increase bitrate to 960 in OTT for lower compression. Turn sharpening on and it should "pop" but it can be a bit too much on some maps. 

 

35 minutes ago, AhSoul said:

've used the OpenComposite tool to make OpenXR the default, and in the Oculus app it says the Oculus Runtime isn't the default, and Steam VR isn't running, but I don't get the OpenXR overlays. So I assume it's using Oculus

You don't need open composite any more. If you use VD set it to VDXR or if you use oculus activate the default open xr runtime in the settings tab. Oculus should prompt you to do this anyway if it is not set. 

Edited January 15, 2024 by Qcumber

[AhSoul]

35 minutes ago, Qcumber said:

I find the opposite with the quest pro. Just make sure you are comparing like for like as I'm not sure the full output from oculus is the same as with VD Godlike. Set the sampling to 1.5 in OTT and see how it looks. Also increase bitrate to 960 in OTT for lower compression. Turn sharpening on and it should "pop" but it can be a bit too much on some maps. 

 

You don't need open composite any more. If you use VD set it to VDXR or if you use oculus activate the default open xr runtime in the settings tab. Oculus should prompt you to do this anyway if it is not set. 

 

I'm trying via Link Cable instead now to see how that goes, and I can't tell if it's using OpenXr or not. The shortcut to bring up the OpenXR ingame menu isn't working which makes me think it isnt?

Edited January 15, 2024 by AhSoul

[Phantom711]

vor 1 Stunde schrieb AhSoul:

I'm trying via Link Cable instead now to see how that goes, and I can't tell if it's using OpenXr or not. The shortcut to bring up the OpenXR ingame menu isn't working which makes me think it isnt?

 

Do you have the OpenXR Toolkit Companion installed? If not, then that menu won‘t show up.

If you are using the dcs.exe from the bin-mt folder, it can not run by anything else but openXR.

And please forget most of that video that you posted…!

[AhSoul]

36 minutes ago, Phantom711 said:

Do you have the OpenXR Toolkit Companion installed? If not, then that menu won‘t show up.

If you are using the dcs.exe from the bin-mt folder, it can not run by anything else but openXR.

And please forget most of that video that you posted…!

Yes OpenXR Toolkit Companion installed and I get the menu when using Virtual Desktop. Just not when using Link Cable.

Edited January 15, 2024 by AhSoul

[Phantom711]

Oh…if you switch between VD and Oculus Link, you must recheck in the Oculus software under options again, that it is set as your „OpenXR runtime“. You need to re-do this everytime after you used VD and intend to use Oculus Link instead (with an OXR application).