FPS drop from smoke and explosion/gun impacts. Any way to mitigate?

[Vitallini]

Hello,

 

Ok, so I've been trying to tune DCS to my liking. My current setup is an rtx 3090, 8700k at 4.9 Ghz, g.skill 2x8 ddr4 at 3500mhz cl15. Pimax 8kx.

 

I can get pretty consistent fps (except when I'm on the run way) at 75 fps when in singleplayer dependent on the scenario of course. I am cpu bound, which is probably not necessary to write :). I believe my fps issues is related to smoke and/or explosions from weapon impacts. Especially long bursts of gun fire or rockets sends me down to 60 fps and it pops back up to 75 fps when the impact smoke has vanished/settled. Its the cpu frame times that are suffering.

 

1. Are there any mods/settings I can change to lessen the fps hit from these effects? I would like to have some reaction in game, but something that is easier on the cpu?

2. Would increasing the amount of ram help with this in any way? From what I gather, it shouldn't, but I felt the need to ask.

3. I want to increase my ram to 32gb to prepare for MP as that looks like fun . I don't want to mix kits as the one I have was bought years ago so I'm looking at a new 2x16gb set. Anyone have a good suggestion on ram for my motherboard which is a z170 asus hero wifi? In dcs, should I focus on Mhz or latency or both?

4. I had an amd 5900x on order yesterday, but looking at more or less same performance on the 10900k at high resolution it hardly looked worth buying a new motherboard to go with the cpu. So I cancelled it. Good decision?

5. My 8700k sits at 72 celsius at highest load on an AIO cooler, will probably reach higher in summer time. I've not overclocked the cpu further as it is stable (perhaps not stress-test stabel, but not experiencing any crashes). I've been thinking about de-lidding the 8700k, but realisticly would a 100 or 200 mhz overclock further mean that much? Worth the hassle?

6. On my system it seems like the f18 is alot more optimized when it relates to fps than the f16. Which plane with a decent campaign(s) is known to be easier on the cpu? I'm not into ww2 planes and a suggestion for a plane thats also popular/usable in MP would be great.

 

Ok, thats about it. I'm gratefull for any input on this.

 

Regards,

 

Vitallini

[Motomouse]

a) Check (for example with fpsVR) frametimes for smoke and explosions. (You did this already, therefor 4 was not a good decision ;-))

 

b) Run mission on dedicated server (for example on the same computer) and compare results

 

c) Use low settings (No supersampling, no AA) and compare results

 

2. and 4. No

 

I play at 90FPS on my 3600x & unlocked 1080Ti & Reverb combo & 100% rendering & super low DCS settings for dogfighting. Try to get high fps by downsampling and then increase from there to find your sweetspot (downsampling also helps with cpu frametimes somewhat). 100% Reverb SteamVR = 2212x2160. Unlocked 1080Ti = 117% Powerlimit & 100% Fan.

[Taz1004]

Especially long bursts of gun fire or rockets sends me down to 60 fps and it pops back up to 75 fps when the impact smoke has vanished/settled. Its the cpu frame times that are suffering.

 

This is normal.

 

Game engine does not calculate anything that's behind solid object. But anything behind transparent/translucent object such as smoke has to be calculated twice. Transparent objects are still the most performance draining.

 

Game engine has to calculate what it originally looks like and then calculate with what it looks like with smoke again. This is not such a big deal if the smoke is far away to cover maybe 100x100 pixel area. Redrawing that much doesn't hurt performance. But if you fire cannons or rockets, the smoke fills up the whole screen and basically everything has to be calculated twice. And that's per camera so in VR, that's 4 times. And this multiplies when you put transparency on top of transparency. And in DCS, everything is already behind transparent canopy.

 

Other instances are when you fill the entire battleground with small distant smokes. Then it'll be pretty much rendering everything twice too.

[Vitallini]

Thanks for your replies guys.

 

Taz1004: thank you for explaining what is happening in this situation. That sounds to me like a slider that would adjust the size of an transparent object like smoke would be usefull right? Probably not easily doable or else it would probably allready be an option.

 

Motomouse: I've been testing a few more scenarios and now I'm not sure if I'm only cpu bound. In some cases it seemed like it was both. Hard to be tell. I checked the link in your sig and read through your guide on vr settings. I've lowered a few of them and eased up on the steamvr supersampling. I found a compromise that in most cases avoided the red cpu frametime spikes which made it mostly smooth. Very long bursts still was a problem though. Anyways, those tips helped me improve the experience so thanks.

 

About canceling the 5900x. I just want to explain to see if my thinking is correct. You've allready said it wasn't, but hear me out :). From the benchmarks I've seen for this chip used with flight simulator 2020 which I think it is plausible that it will have some bearing on dcs performance. The 1% lows didn't seem to be very different from say a 10700k or 10900k. Look at this thread: https://forums.flightsimulator.com/t/amd-5900x-5950x-performance-in-msfs/315580

 

Given that my gun smoke issue when I was testing earlier gave a red spike in fpsvr for cpu and decreased fps from 75 to 60-58: I didn't see the difference observed in the benchmarks to be sufficent to help with the problem. I've read horror stories about people upgrading from systems similar to mine to a 10900k and have very little increase. Now with the new settings I think it would make it better, but I figured I'd wait to see some actual DCS results. I can wait and make a better decision as the new cpu's are tested on dcs.

 

A comment on asw and the pimax 8kx. I've tried it and one of the pros with asw in DCS is that you trade cpu capasity for some visual artifacts which isn't a bad trade off if you don't find asw very distracting. Currently the pimax 8kx delivers 75 frames max. That means that asw is used from a baseline of 37.5 fps. Especially when dogfighting it leads to even more ghosting/skipping of ast moving aircraft and visual artifacts, than the standard 45 fps. I also like the always on asw option in windows mr as you can avoid the jerkiness when going in and out of asw which I personaly find very distracting. For dcs I would use the small fov anyways (atleast in demanding missions) so it isn't that much different from the HP reverb g2 as far as fov is concerned. Also not having to deal with issues with the canted screens on the pimax which mess up zoom to a degree is a pluss. If any one considering a new vr headset for DCS spesifically should stumble into this thread, I believe the reverb g2 would be the better option, but wait for reviews.

[Motomouse]

The 8700k is a very nice CPU

[Vitallini]

Yes it is. I really want to upgrade though. Regardless of Intel or AMD an motherboard upgrade is needed and as I need motherboard with many usb ports (I'm sim racing as well) and they are quite expensive. Jumping on the am4 socket at its end of its life is...not ideal. Bah!

[doclucio]

still big issue today with 2.9 patch, 4090 and 13700k and g2, any idea on how to mitigate?!?

[doclucio]

is there any mod for smoke effects to have less impact?!?

[Burt]

Yup like taz said frame dropping/fluctuation is normal around congested areas- clouds and explosions. Locking to 45 Vsync could help alittle. 

[virgo47]

I can't pinpoint anything in the changelog, but for me, the game crashed with a lot of dust/smoke/shooting into ground/explosions - after the FPS dropped to sub-10 numbers. But with the latest patch it seems manageable. FPS still go down, but not under 10 - and the best thing is - no crash. Anyone else experiences this improvement?