DCS Slows from 60, to 30, then back again..

Hi all, anyone have this issue? DCS runs well enough, I have the usual settings, textures high, detail high, water low, msaa off, DS on, AA through NVidia CP etc.. game does run well enough for me, but using vsync, every so often, my frame rate dies down to 30, then back up again to 60 a few seconds later. Now i do only have 8gb ddr4, so i need another 8 yes, but is this a memory related issue or something else? I have a clean install of 2.5.

Anyone else have a similar issue?

Do you have adaptive V-sync with half-refresh-rate mode turned on in your NV cpl? Sounds like it - the way this method works is keeping 60 and switching to 30 whenever for some reason 60 cannot be maintained.

Try pressing Left Alt + Enter, helps with Fullscreen mode.

Yes sometimes I see the fps dip when I turn on the tgp, and I didn't have that issue in 2.2 nttr. I have not heard of the adaptive refresh rate in cp, so will look into that. This is in single player mode, full screen with and extra screen for mfd export. I have been running the performance monitor in the backround, and my usages are low, sometimes below half on cpu, gpu the same, memory is around 6.9 gigs of 8, so I guess im using the full whack with windows using the remaining, need those extra gigs asap.

Do you have adaptive V-sync with half-refresh-rate mode turned on in your NV cpl? Sounds like it - the way this method works is keeping 60 and switching to 30 whenever for some reason 60 cannot be maintained.

1/2 would keep it at 30 all the time.

with v-sync you have to be able to get fps matching your monitors refreshrate. if your fps drops below monitor Hz you only get half fps. say, your fps drops to 55 with 60Hz monitor, with v-sync enabled you get only 30. in monitoring softwares and their overlays it might seem that you're getting something like 37fps but it's because that fps reading was taken to the overlay from a in fluctuating situation. but in reality, when the fps reading is anything but 60 (60Hz monitor) you are getting only 30.

so using v-sync you really MUST get the fps matching you monitor refreshrate ALL the time. then you get silky smooth experience.

using triplebuffers you can improve that v-sync situation so that insted of dropping to half fps you only drop to 2/3 fps (so 40 instead of 30 with 60 Hz monitor). but that extra buffer induces input lag. you can minimize or even kill that lag by setting prerendered frames to 1. usually when triplebuffers are in use that 1 prerendered frame is all you need in most cases in my experience since there is allways 1 buffer free to write to (as 2 are occupied because of v-sync).

if only 2 framebuffers are in use (normal situation) it's good that there is more than 1 (3 is the default) prerendered frame to be in the queue to that buffer (1 of 2) that just got free to be written on as the double buffer system works little like flipping a card over (1 side is in the screen, the other is written. then it's "flipped" over to the screen, releasing the other side (buffer) to be written.

This is normally the fastest way to render 3d images, but this system (double buffer) is very much in need of prerendered frames because you cannot start writing the next buffer untill it's used and "flipped over" to be written to again. this is also why you need to have the frames to mach the refreshrate, as with v-sync, the image is written on both "sides" of the buffer and then put to screen together, so it kind of waits still untill both buffers are written and put to screen, before it starts the process all over again.THIS gives you the lag you notice in FPS games with v-sync on.

Now if that fps doesnt keep up with this sequence and you dont have the other buffer written in time (the monitor Hz!!!) you only get half the fps.

before this was top and bottom side of the screen, nowdays it can be split to many "stripes" of which half is 1 buffer, the other half the other, thats why you get tearing without v-sync when panning to the sides quickly as the "halfs" get to the screen 1 after another rather than at the same time.

Disable the VSync. It's normal that the FPS fluctuates - you can't guarantee constant 60 FPS.

It's not DCS problem, just VSync which IMO is a piece of cr@# and should be labeled with a clear marking "seriously damages your health" like a pack of cigarettes.

Disable the VSync. It's normal that the FPS fluctuates - you can't guarantee constant 60 FPS.

It's not DCS problem, just VSync which IMO is a piece of cr@# and should be labeled with a clear marking "seriously damages your health" like a pack of cigarettes.

not exactly. just you have to get about 70-80 fps non synced to guarantee 60 fps synced. syncing disrupts the flow of things happening somewhat so it's a drawback no doubt but i wouldnt go as far as saying it's useless.

try that triple buffering trick with only 1 prerendered frame, it manages the flow a bit so you might be able to stay 60 better and if you dont, you only drop to 40. it's not nearly as bad as dropping to 30. it's a noticeable difference!

Plus! using that trick you save some CPU time, which is never bad thing with this game and can help you even more to stay @ 60

Actually, the number of prerendered frames is worth playing with regarless of v-sync being turned on or off. Increasing the value - lets say to 3 or 4 can really help with the micro-stuttering but with a drawback of a higher input lag (noticable with mouse coursor and in-game camera responce delay to real TIR/head movement). Decreasing - opposite, can introduce the micro stutter but reduces the input lag.

Still, I'm not changing my mind about v-sync which is just conceptually a flown idea. It creates way much more problems than the screen tearing it tries to solve.

I concur fully to try out different values for prerendered frames even without v-sync. and i also prefer non synced frames, but sometimes you DO get the smoothest experience with v-sync.

im a tweaker to the core and sometimes i use more time in a week for tweaking and optimizing than gaming itself. for current dcs version i prefer non synced frames. and fps is only secondary what im after, but frametimes i try to get as stable and low as possible. THAT is what really is the thing that gets you the best experience.

When you take your focus out of fps and concentrate on frametimes you get to walhalla. every little bit of stutter is visible in the frametimes even when your fps looks stable. And sometimes you get the lowest stable frametimes with v-sync.

point being, dont restrict your self to any existing idea of not using or using something. look at the frametimes and try to get them as low as possible.

there i have frametimes average 10ms and framerate average +100fps. this is taken third of february in burning skies server. those spikes in the frametime are acceptable in mp enviroment as you cant get rid of spikes caused by people connecting and disconnecting. card is 1070.

11 of february burning skies +30 people in the server

frametime avg of 12ms framerate avg 80fps little bit higher setting but frametimes are still acceptable

When you buy your next Monitor, look for this feature "Gsync". Helps wonders.

Personally, fluent is above anything in a flight sim, together with the lowest possible input lag.

For DCS there is hardly any choice, this is not a turn based game where Vsync may not play role and input lag is "what?". Any flight sim, racing sim, lives off that experience, direct contact, fast visuals, concentrate on the relevant for the flight experience. Anything else is secondary imho.

40Hz, 40fps + input lag ? no way, I'd rather switch off Vsync and accept the downside but stay fast and fluent, quick & dirty I may call that. Nice & slow is not a winner here.

Gsync, if possible check it out on a friend's PC. You will be amazed.

Or FreeSync, if you are an AMD user. I just dont know if FS is as good as GS.

When you buy your next Monitor, look for this feature "Gsync". Helps wonders.

 

Personally, fluent is above anything in a flight sim, together with the lowest possible input lag.

 

 

For DCS there is hardly any choice, this is not a turn based game where Vsync may not play role and input lag is "what?". Any flight sim, racing sim, lives off that experience, direct contact, fast visuals, concentrate on the relevant for the flight experience. Anything else is secondary imho.

 

40Hz, 40fps + input lag ? no way, I'd rather switch off Vsync and accept the downside but stay fast and fluent, quick & dirty I may call that. Nice & slow is not a winner here.

 

Gsync, if possible check it out on a friend's PC. You will be amazed.

Or FreeSync, if you are an AMD user. I just dont know if FS is as good as GS.

+1 :thumbup:.

I used to play FPS a lot and didn't know a single person that would use or say anything positive about v-sync. DCS is the first community where I see a lot of people using it. Funny you mention the turn based games but personally I couldn't stand the mouse rubber-banding v-sync causes even in a game like Civ V.

Though I guess different people are sensitive to different things. With V-sync On the TIR makes me feel almost seasick. While I can't stand the input lag I get the point that some hate the screen tearing.

Anyway, adaptive sync like a G-Sync is a great thing - not only it's a better tech but the concept behind it actually makes sense - which is not a case with v-sync. I agree it's all worth the money and once you experiance a high refresh rate monitor with G-Sync there is no going back.

Thanks all, some great information here. I use v-sync primarily to prevent screen tearing, but I will try without and see how it goes. I did some testing with settings after looking through Snako's thread, and put terrain textures to low, I didn't notice any difference in quality and I seemed to maintain the 60fps more, only in areas with a lot of ground buildings did it dip under 50, so maybe that helped my vram usage as my card only has 3gb, needs more testing..

Once again, thanks for the help ;)

I cant stand the screen tearing. VSYNC is a must as far as I am concerned.

What I found to work best is in-game V-sync off and Nvidia Cont. Pan. V-sync set to Fast.

What I found to work best is in-game V-sync off and Nvidia Cont. Pan. V-sync set to Fast.

Thanks for the tip, disabled vsync in game and enabled fast v sync in CP, I'm seeing frame rates over 100 now, average low 90's, some difference. No slow downs at least none I have seen as yet. Will try a campaign soon and see how that goes ;)

Thankyou again!!