Smoke a Framerate Killer?

[zafgev]

My rig:- I7-4770K, MSI GTX 1080, 16GB RAM, SSD, HTC Vive, 31st Jan stable release SteamVR drivers. Please note I was using the in DCS FPS counter. No clouds in any scenario I tested.

 

I've been trying to figure out - as many of you are - which specific graphical settings influence frame rates. I run a GTX1080 so in theory it should scream in DCS. Non-VR this is absolutely the case - no complaints there. However in VR there is a noticeable drop in framerates no matter what the mission or scenarios are.

 

So to be clear on my statement above I was running 1.5 PD. Most settings were set on high, no shadows, 4X AA, no HDR - basically everything on and off based on other's findings. Steam VR has Asynch Reprojection on. Now with this setup I have never ever seen anything above 40fps. When I hear people saying they run at 90fps I go WTF as technically my rig should at least see 45 fps.

 

So last night I turned every graphical setting down to its lowest settings or off and I set PD of 1.0. I tested this on a MP server to see some network load as well. For the first time I saw my FPS pegged at 90fps (please note no smoke stacks present). So obviously I knew some setting/s had to be the reason for the dramatic drop in fps before. I started turning things up individually, flying, tuning and so on.

 

The only settings in the end that had a real adverse effect on framerates were shadow settings, water and pixel density. Turning up shadows immediately saw my system strain. Turning up shadows saw the fps drop from 85-90 to 40-45. With shadows off and turning up PD to 1.5 (my preferred setting) saw FPS plummet to 28-35fps.

 

So at lowest graphical settings with a PD of 1.5 I get less than 40fps and with a PD of 1.0 I get 90fps. My question is therefore how this is possible? In theory all it is doing is rendering/down-scaling at a higher resolution in 1.5PD compared to 1.0PD, but at such low graphical settings I should not be seeing such a dramatic drop in framerate. I mean a GTX1080 is made for 4K so this should be a breeze right?

 

The second real issue is any type of volumetric rendering (actually I'm not even sure if DCS does volumetric rendering) - lets call is clouds and smoke. With lowest settings at a PD of 1.0 I did also notice than in mission type scenes where smoke stacks are rendered I see a big drop in FPS. Turn away from it the FPS spikes up again, turn towards them the FPS drops. To be honest I have never really seen a sim that does not have a rendering hit when smoke/fire modeling is rendered so no surprises here. However is there any tuning advice for simplifying smoke rendering to have less of a hit on performance?

 

Sorry for the long write-up - perhaps this helps someone - by not feeling alone - who has the same issues and has not yet had the time to test or figure things out.

 

If you have any ideas to help me out please shout. Cheers and thanks.

[fitness88]

I use Rift and one good thing at 90 or 45 I don't see much of a noticeable difference if any, others mention if you look for it you'll see it but I haven't yet. For this reason I turned up my graphics. I did a lot of tweaking and found if you use the video card control panel it won't do anything for your performance as it doesn't communicate with Rift or Vive, this comes from Nvidia.

I'm also told that 1.5 PD is the sweet spot over that and your over spending. No shadows never liked them, low or med water, heat plume off msaa x8 anisotropic x8, terrain/textures high....lots of trial and error.

In fact I find at lower FPS VR way out performs multi monitors.

[dburne]

I use Rift and one good thing at 90 or 45 I don't see much of a noticeable difference if any,

 

Neither do I , in fact if it were not for the gun-sight acting up in the Spit when ASW is running I would not even know... well other than the frame-rate counter.

I think Oculus did a good job with this feature.

[RUS38]

I'm on 980ti and ASW is horrible. I like how it makes dcs very smooth and I don't mind that some things get blurry with ASW but I get stutter every few seconds and that makes it unplayable for me with ASW on. Does anyone else have this problem?