Performance Sanity Check

[lucky-hendrix]

Hi Guys,

I have recently upgraded my GPU, and thus I wanted to try DCS in VR again. However, it seems to me that my performance are  quite under what I should be getting comparing to what some other are reporting in various places over these forums.

I have already went trough a general tuning of my system, clean up& small OC to get the most of my hardware, and when in non-VR   all seems fine.

However in DCS I have trouble obtaining correct performances, I know that DCS is notariously difficult for this, but still, as I said above, I often see post in these forum that suggest I should be able to get fluid VR with at least OK-decent eye-candy.

My VR headset is a HP Reverb G2 & I have read about the report of issue with the V1 cable, and I am wondering if some of my problems couldn't be explained by this. As Even in much less demanding tittles (IL2 for instance) even if my frame times are very good  most of the time, I will start to see red spikes in the frame time, and very often SteamVR will crash within 1hr of play.

 

So here is my config :

CPU : I7-7700K

GPU: RTX3070Ti

RAM : 48Gb DDR4 @3200MhZ

VR heaset : HP ReverbG2

 

What should I expect in terms of performances in DCS ?

Currently withe Graphical preset 'VR' in DCS; DCS pixel density 1.0; 100% pixel density in steamVR Global settings; I have to reduce the 'per app' pixel density for DCS to 60% to have something playable, and even then I still have occasional stutter and SteamVR will crash after a longer play.

I usually 'benchmark' by starting always the same instant action mission : 'On Alert 5' on the Persian Gulf in a  F-14B

 

[edmuss]

Switch to OpenXR and as long as you're happy with running reprojection or slightly lower settings then you should be ok.  The crappy amount of VRAM may hold you back a bit on some maps/modules.  Needless to say, get your processor overclocked as much as possible, I would guess that it will be starting to hold you back with clockspeeds and raw horsepower.

DCS via steamvr has a vram memory hole somewhere that causes the frametimes to tank, it can be temporarily alleviated by alt tabbing till they settle and then resuming, it's not a 100% fix though.  OpenXR uses less vram so it less prone to the problem, I do still come across it once in a blue moon if I have settings cranked up high.

On my 3070 it only makes a couple of ms difference in frametimes from VR preset to mostly high but it does have a significant impact on image quality.  My two main avenues of attack for tuning DCS with openxr is as follows: -

Run the reverb at 60Hz and 80% render resolution with motion reprojection turned off and adjust the settings to achieve >60 fps, on my system this is generally high textures and most of the other settings medium.  By beating the 60 fps refresh rate you get syncronised displays and it's super smooth without artifacts, downside is the reverb has a refresh rate flicker at 60Hz that some people can't stomach.

or

Run the reverb at 90Hz and 100% render resolution with motion reporojection turned on and adjust the settings to achieve >40 fps, on my system this is high across the board apart from view distance, shadows and clouds on medium.  Motion reprojection keeps the displays smooth but it does artifact a little, the additional GPU headroom allows you to push the settings up though.

Up until recently the reprojection in openxr caused significant artifacts but it seems much better now (although still not quite as good as steamvr implementation); additionally the openxr reprojection can step down in multiple fractions (half/third/quarter) of the refresh rate whereby steamvr can only step down to half refresh - this is super powerful because it allows smooth display down to about 35 fps.

 

 

 

[lucky-hendrix]

Thanks, Indeed I will try OpenXR & report back.

but I feel like my problem is deeper than that. Do you remember what setting you used back when using SteamVR? (to have an apples to apples comparison ) Did you ever have steamVR crash often? Because Even if a lower a lot the settings, while I can have frame times under 15ms 95% of the time, I will still see moments where I see frame times that jump to 40-60ms every second and still have SteamVR crash on me after a while.

[TylerPL666]

On 5/18/2022 at 3:34 PM, lucky-hendrix said:

RAM : 48Gb DDR4 @3200MhZ

What exacly u have? 2x8GB+2x16GB? 

+ I spend 4 days optimising my PC and searching for my sweet spot. Follow those two and u will find your optimal settings. Be awere that VR is nothing to compare with 2d image settings optimizing. To be honest I struggle for months before I finnaly understand, that "CURE" for bootleneck in my situation was to PUSH settings UP - clouds, water, even textures to HIGH/Ultra and lowering shadows. Now I have rendertimes in OPENXR (All default resolutions) CPU ~14-15ms, GPU ~15-16ms in Apache in MP over Krymsk/Krasno. And forget about any mods for now - every mod can easy break frames

 

Edit:

How To Nail Your G1 & G2 Setup Optimized for Outstanding Views

Edited May 20, 2022 by TylerPL666

[lucky-hendrix]

Just now, TylerPL666 said:

What exacly u have? 

2x8Gb G.Skills Ripjaws 5  + 2x16Gb G.Skills Ripjaws 5

I upgraded recently, but except the size all specs are the same, latency, timings, frequency, ...

[Phantom88]

If you are running Win11 as your OS try turning HAGS off in your setting to see if that helps

[lucky-hendrix]

I run win10.

 

Just tried openXR and damn, this is a serious improvement ... 

Just wish there was tool similar to fpsVR so I could see it quantatively rather than my own impression. 

But still my question holds, for those with a system similar to mine, what can I expect to be able to run in terms of DCS settings and Pixel density ? 

[edmuss]

3 hours ago, lucky-hendrix said:

Thanks, Indry OpenXR & report back.

but I feel like my problem is deeper than that. Do you remember what setting you used back when using SteamVR? (to have an apples to apples comparison ) Did you ever have steamVR crash often? Because Even if a lower a lot the settings, while I can have frame times under 15ms 95% of the time, I will still see moments where I see frame times that jump to 40-60ms every second and still have SteamVR crash on me after a while.

In steamvr I used 60hz with reprojection down to 30hz but that was also bouyed up with FSR and shader mods. Steamvr was pretty stable with regards to crashes if you ignore the vram hole, however with HAGS on the memory hole problem didn't happen but steamvr would crash.

The frametime tanking to 40-60 sounds very much like the vram hole bug, it will most often occur if you were to fly a new mission without restarting DCS or respawn. Fpsvr will show it as dropping frames constantly.

Openxr is better on vram usage so the vram bug instances are few and far between, very occasionally it does grind to a halt but that's normally when the settings really are too high.

Edited May 18, 2022 by edmuss

[lucky-hendrix]

2 hours ago, edmuss said:

The frametime tanking to 40-60 sounds very much like the vram hole bug, it will most often occur if you were to fly a new mission without restarting DCS or respawn. Fpsvr will show it as dropping frames constantly.

Interesting I haven't heard this bug described like that, but it does indeed seem to correspond to what I am experiencing ! Would explain a lot.