Ka50 2 and 3 and frametime spikes

[Comante]

I have a G2 that run on a 1080 and a I7-4790K, 16 GB ram.
I've recently switched to foveated rendering and this allowed me to decide if I want to run 30 FPS with reprojection or 60 FPS without it.
The main problem has always been with helos, reprojection + cockpit shadow +low level flying =  mess , so I decided to lower some detail and see if it can achieve 60 fps (without cockpit shadows).
Well, it definitely can with turbo and reproj = off, BUT FPS drop to 55 (stutters included) at a regular pace, every few seconds. The frametime graph look like a saw, I thought this is related to the rotor ... someone already know this and found a solution?
Cheers

[average_pilot]

I've noticed that.

Interestingly enough, the same mission in the same map with the same assets can be perfectly smooth when flown on fixed wing aircraft instead of a helicopter, even flying very low and slow over busy cities. Go figure...

After much back and forth I finally gave up on two things: terrain shadows and high textures. Despite the negative visual impact I'm happier keeping those 60fps constant and removing most of the spikes. I still have shadows inside the cockpit and I don't really miss the shadows outside the cockpit that much.

Textures at medium can be a problem with older modules. I selectively double the textures of older modules (for example, Su-25A/T) with xnresize so that they show with good quality in game at medium textures. Quite absurd if you think about it. If that setting worked differently and capped the size of the texutres instead of halving all the textures no matter the size that wouldn't be necessary.

Yet another tip that seems to help is removing the DCS process from core 0. And that even obscurer tip of alt-tab out of DCS during loads... who knows if it really works, but now I do that almost always just in case.

I'm using MT.

BTW, the latest optimization of the Syria map helped a lot with this.

[Comante]

Yesterday I investigated this issue a bit, and the only factor I found that affect those spikes is resolution. Decreasing it, the spike decrease in "height" to the point that the simulator is able to keep 60 frames. For my system this happen around 50% resolution, on the contrary, with fixed wing aircraft I can keep consistently 65 70% resolution if I don't want to use reprojection.
The decrease in resolution free resources, so that It can have cockpit shadows low + blur without a hitch...

[average_pilot]

Yes, resolution is the most important performance factor. I've myself found the limit with my current system is around 48% without fovetead rendering. I started using fixed fovetead rendering a few weeks ago and now I can go up to 60% without those stutters we are talking about. But because more often than not people usually say to be using crazy resolution levels like 150% and complain how anything below is unbearable I stopped talking about resolution despite being like I said the most important factor by a long shot.

Still, terrain shadows off, textures to medium and affinity to all cores but zero core helped me to eliminated the performance spikes without sacrificing even more resolution, which is a precious resource in VR. Textures is perhaps one of the most important because once the VRAM is full the system (I don't know if that happens at SO level or driver level or a mix) starts swapping chunks of data between RAM and VRAM and performance goes down the drain. When you are at the limit it manifest as stutters as you look around.

This is maybe going a bit off topic, but isn't it infuriating that a headset with much more resolution like the Varjo Aero gives better performance than the G2 when resolution is the major drag when using the G2? I wonder what bottleneck there is in the software stack of the G2 that isn't present in the Aero. So frustrating.

[Comante]

I don't know, the Vario is another league, WMR headset are dinosaurs and the G2 is the only good thing born from WMR, I can't pretend more... if you think that most of what we have has been made by Mbucchia in his spare time.. sad.

[edmuss]

5 hours ago, average_pilot said:

his is maybe going a bit off topic, but isn't it infuriating that a headset with much more resolution like the Varjo Aero gives better performance than the G2 when resolution is the major drag when using the G2? I wonder what bottleneck there is in the software stack of the G2 that isn't present in the Aero. So frustrating.

The trick with the aero is that whilst it's very high resolution, it's only a tiny area that you're rendering.
Pixel count on a G2 at 100% resolution is 19.5mp
Pixel count on an aero at maximum resolution is 14mp

Run the aero as a stereo render (as per the G2) and it will be worse performance than the G2.

@Comante Unfortunately I think you may just be trying to push too much through with the G2/1080 combo, but you have to make best of what you can!

You're limited on VRAM capacity so 100% check out Taz's optimised textures, it will help.
BS3 has the blurred rotor mast tech inherited from the ah64, it eats 8-10fps with my 3080ti when it gets up to full speed.  I believe that BS2 isn't afflicted so you will get better performance.

 

If you're running the G2 @60Hz then it's great if you can keep the frames high enough, however if you dip below then it gets very rough.  It wasn't until I upgraded to the 3080ti could I keep the frames >65fps constantly.  2.9 gave some performance improvements but you can't leverage the big one of DLSS because you're on a GTX

Edited December 12, 2023 by edmuss

[Comante]

I know, but in reality I'm really happy about the 1080 performance, consider that I flew 1 year with a 1060... the thing that buzz me is just the difference in performance from F16/18 to Ka50-II ... the BS3 is too demanding to achieve 60 fps probably even at 50% resolution.
btw foveated rendering is a bless! I will have to give another try at FSR , recently I found that the frametime cost was not worth the hassle as the quality sensibly deteriorated. But maybe without reprojection it could be better.
Will look for taz textures, even if I don't reach the 8gb limit, low texture are quite sad even in VR.

[edmuss]

Helos are system intensive unfortunately, always pull less FPS in rotary wing. Not helped by the fact that you naturally want to turn up all of the eye candy down low!

Generally I found that reducing the resolution have a better result then upscaling for me. The upscaling has a computational GPU cost (alleviated somewhat with DLSS as it's run on the RTX tensor cores) and the benefit was outweighed. It may be different with the native 2.9 upscalers, with openxr toolkit I found NIS to give a better image than FSR.