Degraded performance (stuttering) compared to similar aircraft

[bernardv]

Hi,

I've noticed considerably worse FPS and stuttering when using A-10C2 compared to F-18 for example. This would be on the same map, same starting position on the runway, same settings... This is noticeable in VR in particular, when doing startup on some large airfield for example. Is there any reason for A-10C2 to take significantly more HW resources than F-18 and other planes or is it just implemented in a  less optimal way? It is my impression that this module clogs the already clogged main DCS CPU thread even further, but it's just a hunch.

Cheers

[BIGNEWY]

Please let us know your system spec. 

If you are NVIDIA check your NVIDIA control panel, setting max FPS for background task and the Max fps has helped some users. 

Set them both to your screens refresh rate, it may help. 

[bernardv]

I've got GTX 1080, Ryzen 5600X, 32 GB RAM, 1T NVMe disk.  For VR I'm using Quest 2 (tried both Air and USB link), but it was similar on Rift S. My monitor is LG 32GN600-B with variable refresh rate up to 165Hz set to 120Hz for my Windows desktop. I use DCS in VR only.

In an F-18 I get some degraded FPS flying over Dubai for example, otherwise it's fine. In an A10C2 I get low FPS/stuttering right away at any larger airport (Nellis, Dubai ...) when doing startup. On smaller airports and on most of Caucasus map It's much better, basically playable. Again, an F18 is playable everywhere for me.

[BIGNEWY]

take a screenshot of your DCS settings page and attach it here, also attach your dcs.log from your saved games dcs folder we maybe able to suggests some tweaks 

[bernardv]

Here you go. I'm under the impression my settings are quite well optimized, but hey, I might be wrong

dcs.log

[BIGNEWY]

settings look fine. 

some shader errors in your log however. 

Can I check windows and your display driver are up to date? 
Are you using any shader mods?

It maybe worth going to your dcs folder in the saved games location, delete the metashader2 and fxo folder, restart dcs and test a single player mission, give it time to rebuild the shaders. 

[bernardv]

I tried out some VR mods some time ago but I removed them soon, restored original bazar folders from backup. Refreshing these shader folders under saved games didn't make any difference. As I noted before; either this plane takes a higher toll on the main CPU thread or it's simply the quality of the textures and the level of detail in the cockpit that take a higher toll on the GPU. Perhaps more than 8 GB of VRAM would be optimal for a clear cockpit view of A10C in VR? Something like 6900 XT? Or can some upcoming Vulkan magic do the trick in the near future?

Edited January 21, 2022 by bernardv

[jaylw314]

I've the A-10C2, F-16C, F/A-18C, and I've flown VR with a RX 5700XT and RX 6800XT.  I've not seen significant differences in performance, so yours does not sound like a universal problem, which still suggests some individual troubleshooting and hopeful solution.

 

[bernardv]

I think I figured this out. Looks like DCS is only able to run VR at 45 or 90 fps (I don't think it can even tell it's a Quest 2 headset, it just assumes it's Rift S). Quest 2 default for Air link is 72 Hz and that doesn't mix well with 45/90. After I switched to 90 Hz in Oculus settings the stuttering went away. Still I have no idea how this didn't affect F18 or any of the FC3 planes, just the A10C2.

PS

One explanation could be that this resynchronization from 45/90 to 72 takes an extra toll on the GPU. With simpler planes I was at the point where my GPU could still handle this, but with A10C2 it was just the last drop that pushed the GPU over the edge. 

PPS

In the end it looks like it's simply a Quest 2 tracking issue, which occurs under high load of all components involved when using Air Link. If this stuttering starts to happen, the simplest way to resolve it is by just pausing the game and taking the headset off for a second to reset room-scale tracking on Quest level. With lower bit rates, simpler missions and planes, lower rendering resolution this is a non-issue, doesn't happen. With everything cranked up and when the mission starts in some cluttered environment in a more complex plane like A10C2...

Edited January 26, 2022 by bernardv