High end rig - low FPS with medium settings despite low CPU/GPU utilisation

[VC]

I have a rig I believe should be quite capable for VR:

 

i5-9600K

RTX 2080

32GB RAM

DCS on dedicated SSD

 

Headset is the HTC Vive (original one).

 

I've read a lot of setting optimisation threads and played around, they all converge on similar suggestions. Here's what I'm running:

 

SteamVR Supersampling 200%

PD 1.0 in game (I prefer using SteamVR for the SS)

 

nVidia control panel - prefer maxium performance

 

textures - high

terrain textures - high

civ traffic - off

water - medium

visib range - high

heat blur - off

shadows - medium

depth of field - off

lens effects - none

motion blur - off

cockpit displays - 1024

MSAA - 0x

SSAA - off

clutter grass - 0

trees - 75%

preload - 75000

chimney smoke - 0

gamma - 1.8

Anisotropic filtering - 2x

terrain object shadows - flat

cockpit global illumination - off

 

And I still can't hit 90 FPS on a clear day on Caucasus. I have about 80-85 FPS, which is pretty good, and I don't drop below 45 even in busy dogfights so I guess I should be happy. But what really bothers me is that CPU and GPU utilisation are hovering around only 50%. Increasing any settings leads to FPS loss quite quickly, but CPU and GPU aren't working any harder. I'd love to crank SS a bit higher and/or add some MSAA. I've seen people claim to run 1.5 PD (quivalent 225% SS) with 2x MSAA, or 1.8 or 2.0 PD, and still get 90 FPS with older processors and 1080s. I'm hovering around 60 FPS at best with those kind of settings.

 

I'd just like to understand why the performance and utilisation seem so mis-matched. Is there anything else that I can optimise?

[BIGNEWY]

I wouldn't worry about utilisation, if you are getting good frames and it is smooth turn off the frame counter :)

 

I run mine at much lower settings, steam VR supersampling below 100% and use 1.2PD in game, it looks fine for me but it is personal preference.

[The_Ant]

Turn down Shadow to flat and visib range to medium,should give you some fps,dont expect much.Many people WRONGLY THINK that when they have a high end machine,they can run in 90 fps on high/max settings in Dcs or il2.Theres NO computer with todays TECH,that can do that,maybe in 5 years time with better cpus and gpus,you can get higher results.Be happy with a constant 60 fps thats good.I have high end machine,having had the first oculus rift when it came out,and now using a rift-s and happy as hell,im using similar settings as you do,and doing around 60-70 fps in dcs and in Il2 and im happy,just experiment with the settings,untill you find something thats high and constant in fps,and go from there.

[VC]

Turn down Shadow to flat and visib range to medium,should give you some fps,dont expect much.Many people WRONGLY THINK that when they have a high end machine,they can run in 90 fps on high/max settings in Dcs or il2.Theres NO computer with todays TECH,that can do that,maybe in 5 years time with better cpus and gpus,you can get higher results.Be happy with a constant 60 fps thats good.I have high end machine,having had the first oculus rift when it came out,and now using a rift-s and happy as hell,im using similar settings as you do,and doing around 60-70 fps in dcs and in Il2 and im happy,just experiment with the settings,untill you find something thats high and constant in fps,and go from there.

 

Funny you mention IL2. I am revisting DCS settings and posting this (although it's been discussed before) partly because I got back to IL2 recently and with some settings tweaks I get steady 90 FPS even in a busy MP dogfight, with same SS I use in DCS and most game settings on high. I can't seem to get the same combination of picture quality and performance in DCS. It's possibly because modern plane cockpits with MFDs and HUDs are much more demanding to read, and since spotting is significantly worse in DCS than IL2. Anyway, I feel IL2 is way better optimised for VR than DCS. Not that DCS doesn't look great, but more compromises need to be made as I said.

 

Anyway, I have terrain object shadows on flat already. Main shadows I feel I can't go below medium because it affects the shadow of e.g. the cockpit canopy frame as it passes over the instrument panel, and it really ruins the immersion if that's a jagged mess.

 

I'll play with Visib range. I think last time I had it on medium it made flying in mountains very weird, because huge peaks not that far away are invisible until they "pop" into view as they render and it's jarring.

 

I'm not after max settings, I know that's not possible. But I'm not even close to max settings. I worry about utilisation only because it would be nice to know if there is a hidden bottleneck or something.

[toutenglisse]

VC : my opinion about what you see fps/usage wise :

 

GPU usage, in my experience, is quite right whatever the monitoring resolution you use (usually it's 1 sec for each data record by default).

 

CPU usage, on the other hand, is really to take as an average with default resolution. For exemple on a given scenario I was seeing a 40% usage on all cores with 1 sec resolution, quite stable and only variating for like 10% up or down, but according to an other user's expertise I tried a 1/10th of a second resolution and the observation was totally different : all cores spiking crazy, hitting 100% "all the time" one after the other cores.

 

If you use reprojection at 45Hz, the CPU usage won't be an issue, a limitation. But if you don't and let the sim render as many frames as possible from rig, the CPU usage will be topping 100% very quickly but you won't notice it with a standard resolution. (Grain of salt : considering you use "homogenous" settings, wich seems to me the case, because if you place GPU in a case it's the limiter, with 3.0 PD lol for exemple, you won't see CPU being much used)

 

It's what I see, but try yourself because we don't have same rig and maybe it's different for you IDK for sure.

 

Considering your rig and settings, I find them OK - I use just some with different values but to me yours are homogeneous, and by the way it's a matter of taste.

That said, considering the room you have with GPU, you can add 2x msaa, max aniso-filtering, cockpit illumination.

I put water on max and vis.range on medium, grass and trees at 90%, and considering you have 32GB : preload on max (also set a 32GB virtual mem on SSD in addition to your 32GB Ram)

[DeltaMike]

CPU utilization is meaningless, DCS isn't multi-threaded. You are CPU limited, but not by much, you have a fine system. If/when you upgrade your HMD you'll work the GPU harder.

 

You can crank the anisotropic filtering if you want. May need to back off on shadows and vis range on a busy multiplayer server.

[VC]

Thanks guys. I did a bit more testing and I am getting steady 70 FPS in SP free flight with 2x MSAA.

 

Anisotropic I'm not sure on. 2x to 16x is an enormous performance hit and in the past I have not seen much visual benefit from it. Personal preference I guess.

 

For CPU, looking closer I can see some cores spike to 80% utilisation at times, I guess that's still single thread limited though. I'll ignore that one.

 

For GPU, I've pushed the utilisation up to ~80% with the MSAA and other tweaks. The thing that's always maxed out is the VRAM usage. :(

 

I need to spend a bit more time actually flying with the new settings (I was doing FPS testing without actually wearing the HMD) to see if I'm 100% happy with the image quality and spotting.

Edited August 25, 2019 by VC