Fluctuating FPS

[Thorsten]

Tried UFO, very little change in FPS, maybe one or two more per minute, But still very jittery fluctuates between 3 FPS and about 19 FPS no change if I disable everything such as AI, 3d clouds, particles, ETC, even with basic weather, and no METAR, still no change, tried clearing the navdata with %appdata% command in "run" window, no real change either.

With the ufo looking at clear sky, you should have close to zero rendering and systems load. If you can't run FG with 60 fps under these conditions, there's something more fundamentally wrong.

The only similar thing I've seen here is that it sometimes happens that my Linux gets stuck with a kworker process (I gather these have to do with how the Kernel manages multi-CPU utilization). If that happens, FG starts up at glacial speeds no matter rendering or systems settings because it doesn't get enough CPU time allocated.

I don't know what OS you're on, but under Linux a top might be a good idea at this point. I have no idea whether there's something similar under Windows.

[Clive2670]

Hi Thorsten, I'm running Windows 10, Just tried 2016.3.1, and 2016.4.1 switched off all weather (No clouds) pointed up in the sky using UFO as you suggested, still only getting between 6 and 20 FPS on both versions of FG, I am running a Toshiba laptop, with a Intel i5 4210U processor (Dual core, Logical processors 4) Intel 4400 graphics (Auto switching to a AMD Radeon R7-M260, 1Gb card when loaded) 6 Gb RAM. 1Tb hard drive ( 69% free space) Current useage of memory with Flightgear running is: 4.1Gb and my processor utilization is: 27% Automactic overclocking is to 2.57 Ghz from normal full power of 2.4Ghz My scenery folder is the complete world (Downloaded via Terramaster 1.4) Terrasync is switched OFF. I don't know if these statistics are of any use to you?

[Thorsten]

Do other (especially 3d) applications run okay? Does the system dig into swap?

Auto switching to a AMD Radeon R7-M260,

Does this happen for sure?

[Clive2670]

Hi Thorsten, Yes all other things run fine, Checked with MSI afterburner for AMD Radeon card, and yes graphics are switching normally (To R7-M260 card) and operating with FG, All temps' are well within parameters (hovers around 63 degrees on the GPU) "Max' out" is 100 degrees so nothing wrong there, I have made sure I'm running the latest drivers as well. I'm now going to try downloading and running ubuntu on here via a 32Gb SD card, and run FG exclusively on ubuntu just to see if that works

[Thorsten]

It feels like FG is denied resources from your OS (CPU most likely, this doesn't smell rendering-related), but as to why this happens, I have no clue...

[Clive2670]

Ok thanks for all of your help Thorsten, I will plod on at the current FPS and hope that the next release 2017.1.1 might be more stable!!!

[Thorsten]

To be clear: I don't think this is an FG-side problem - I think there's something weird going on OS-side that prevents FG from getting systems resources. There's no way FG with no rendering or systems load would produce 6 fps on a modern computer.

So unfortunately I am fairly convinced a next release won't change the situation (knowing next to nothing about Windows 10, I can't give any solid hints where to look either). Maybe you need to register FG explicitly for some high-performance mode, maybe there's a virus scanner active that watches every step it does that needs to be convinced to back off - I believe it's something like that.

[Richard]

It does sound like a system related problem, such as thermal throttling, having the wrong settings in the power plan, or somesuch.

Suggest downloading a hardware / temperature monitor (such as http://openhardwaremonitor.org/) and see what's going on. Also need to see the CPU stats and GPU stats (temps, utilisation).

When I last used my laptop it achieved 8-20 fps on (i7 Win10, HD graphics). If I position myself in the middle of an ocean or look at the sky it was 30-45 fps (F-14 2014 dev version).

[Clive2670]

UPDATE- for all that have inputted info' on trying to sort this problem, I think I have tracked it down.....NOTHING to do with FG itself, It seems to be a AMD driver issue, After some extensive "digging" around on t' internet, I've found out that there is an issue with the AMD drivers for mine (and many) cards with.....WAIT FOR IT.......stuttering games and video!!! Now trying a different driver to see if it cures the problem! I will post back my results, thanks all that have contributed

[Clive2670]

Just downloaded and installed "Hotfix 16.1" for AMD cards running the Crimson Drivers....and WOW what a difference, Now getting between 16 and 24 FPS STABLE, with MP running, Live weather, 3D clouds, Precipiptation, Dust ECT, Random Objects, Random Veg' (1) Shaders are maxed out except "Urban" & "Landmass" what a difference (Google makes!!!)

[Johan G]

Internet + Google search is probably the best thing that happened to mankind since the printed word.

[Clive2670]

UPDATE TO ALL: I have found the (REAL) culprit, nothing to do with the program, the drivers, or anything else......It was Windows settings or to be more precise, the vitual memory, (or lack of it) it was running at system managed size, 1028Mb so I upped it to 5120Mb minimum and 10280Mb maximum. I am lucky I have a 1Tb hard drive and have a "shed load" of free space to do it! Now my F.P.S is fairly stable with all weather, shaders, AI, and all the bells and whistles switched on, I am averaging between 18 & 22 F.P.S. Turn off a lot of the not needed stuff when flying at FL330 and I can get 30+ FPS with the 777-200LR. So as you can work out in my post 10/02/17 that download "fix" didn't work for long, So word of advice also check your system properties virtual RAM settings as this could be the CAUSE of your issues!!! Thanks to all that have posted!!!

[bugman]

Maybe it would be useful to add something to the FlightGear FAQ, specifically:

[wiki] Frequently asked questions#Why is FlightGear so slow?

Or maybe add a new FAQ entry. 1 Gb of virtual memory is no where near enough for modern MS Windows systems! With that you have memory swapping issues slowing everything down, not only FG.

Regards,
Edward

[bugman]

Good Idea Edward, will do that now

[GlynD02]

Just tried resetting my virtual memory on a Windows 10 64-bit PC. I can now get fairly decent frame rates with the vegetation set to high, thanks Clive. Still can't go to very high though, however it certainly looks a lot better than medium as I prefer a "low and slow" helicopter in the sim...

Cheers