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Low Framerate

Graphics issues like: bad framerates, weird colors, OpenGL errors etc. Bad graphics ar usually the result of bad graphics cards or drivers.
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- what OS (Windows Xp/Vista, Mac etc.) are you running?
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- what graphics card do you have?
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Re: Low Framerate

Postby Robertfm » Wed Nov 06, 2019 7:45 pm

Well my frame rate issue has returned. It only seems to happen when I have been flying for a couple of hours. I have been monitoring CPU & GPU rate and my GPU never gets above 25%. The CPU averages 60%. I've looked up reasons for this but nothing seems to fit. I have altered power settings to Ultimate. I am perplexed. Why isn't FG utilising the GPU there is plenty of CPU.

Forgot to say when I quit FG and then restart my FPM goes back to 60. When I first started using this computer I was getting FPM of 120+.
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Re: Low Framerate

Postby V12 » Wed Nov 06, 2019 9:00 pm

I have similar problem, too. And on all of my machines.
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Re: Low Framerate

Postby wkitty42 » Wed Nov 06, 2019 9:23 pm

check your memory consumption, as well... depending on your OS and the amount of memory you have available, you may be swapping to disk...
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Re: Low Framerate

Postby Robertfm » Wed Nov 06, 2019 9:32 pm

I have 16gb ram and a TB processor with a further 500gb additional drive. Just check task manager with plane running on runway. CPU 31% Memory 1.6GB GPU 18% and Power Usage Very High.
Last edited by Robertfm on Wed Nov 06, 2019 9:40 pm, edited 1 time in total.
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Re: Low Framerate

Postby V12 » Wed Nov 06, 2019 9:40 pm

In my case this is not problem, I tested config with 32 GB RAM on LUbuntu 18.04, FG consumed only 12 GB, swap partition was not used. Now I'm flying on 16GB, system start swap only in case of the long trans Europe flight for example LXGB to ESSA.
IMHO, fps drop is proportional to the flight time, not distance.

When I spawn with UFO at LOWI, I have nice 30 fps. After 10 hours without any movement, fps drop down to 10 fps without significant memory consumption.
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Re: Low Framerate

Postby legoboyvdlp » Wed Nov 06, 2019 9:52 pm

How many CPU cores?

I thought I had low % useage but I had one core at 85% and one at 10% - the Resource Monitor actually shows what's going on :)

Are you all using advanced weather because I do find after a lot of tiles / weather points are loaded reloading AW helps if performance drops to unnaceptable levels (which happens only sometimes).
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Re: Low Framerate

Postby Robertfm » Wed Nov 06, 2019 10:19 pm

I don't us AW I noticed it didn't deliver live weather, at least when I connected with live weather the weather changed, so one of them must be wrong. Anyway back to frame rate. I downloaded a piece of software to do a stress test on GPU. During the stress test GPU was running at 99% & 45fpm. So I set up the plane on runway running and was getting 60fpm. I activated the stress test again and the FG fpm dropped to 24. No idea what this means but thought I would pass info.

I just don't understand why the GPU is not being used to it's capacity by FG but frame rates still drop. I am definitely using my GeForce GTX 1660 Ti for my monitors.
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Re: Low Framerate

Postby Icecode GL » Wed Nov 06, 2019 11:23 pm

I just don't understand why the GPU is not being used to it's capacity by FG but frame rates still drop.


Because the GPU doesn't do anything on its own, it's fed all the time by the CPU. Having the CPU and GPU work 100% all the time is very, very hard. I'd say it's not even possible to get more than 50/60% on legacy APIs like the one we are using. If we introduce async compute with modern APIs like Vulkan and GL > 4.0, we could probably get to 80/90%. A lot of effort is put into real times apps so they can get all the juice they can from the system hardware.

What I'm trying to say is that getting high GPU usage is something that requires a deliberate effort and time. It's not a bug, it's a feature, and its implementation is unfortunately nowhere near close to trivial, specially given the tools we work with.
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Re: Low Framerate

Postby V12 » Thu Nov 07, 2019 6:50 am

legoboyvdlp :
In my case, 4 physical cores, I'm using AW, terrain presampling with terrain effects and thermal generation switched on.
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Re: Low Framerate

Postby Robertfm » Thu Nov 07, 2019 8:51 am

Icecode GL wrote in Wed Nov 06, 2019 11:23 pm:
I just don't understand why the GPU is not being used to it's capacity by FG but frame rates still drop.


Because the GPU doesn't do anything on its own, it's fed all the time by the CPU. Having the CPU and GPU work 100% all the time is very, very hard. I'd say it's not even possible to get more than 50/60% on legacy APIs like the one we are using. If we introduce async compute with modern APIs like Vulkan and GL > 4.0, we could probably get to 80/90%. A lot of effort is put into real times apps so they can get all the juice they can from the system hardware.

What I'm trying to say is that getting high GPU usage is something that requires a deliberate effort and time. It's not a bug, it's a feature, and its implementation is unfortunately nowhere near close to trivial, specially given the tools we work with.


Forgive me if my paraphrase is wrong, 'so you are saying it's the Sim not my system.' So why did I initially receive 120+fpm in game. It has settled back to 60 but drops to less than 30 after several hours flying.
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Re: Low Framerate

Postby SurferTim » Thu Nov 07, 2019 11:16 am

Robertfm wrote in Thu Nov 07, 2019 8:51 am:Forgive me if my paraphrase is wrong, 'so you are saying it's the Sim not my system.' So why did I initially receive 120+fpm in game. It has settled back to 60 but drops to less than 30 after several hours flying.

At the risk of repeating myself, that sounds like a heat problem. If it were my system, I would take the case side cover off and get a small fan to circulate air inside the case, just as a test.

Edit: As I recall, you use Windows 10. There should be utilities available to monitor CPU load and temp.
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Re: Low Framerate

Postby V12 » Thu Nov 07, 2019 11:36 am

Again, in my case, this is not heat problem, because I have CPU loaded only on 30-40% with temp around 50 degs C, GPU (6 GB GTX 1060) load is around 40-50% with temp around 50 degs C too. Both thermal protection activation temperatures are much higher.
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Re: Low Framerate

Postby SurferTim » Thu Nov 07, 2019 11:44 am

I mentioned it only because this caused my system to slow.

I'm running FG 2019.2.0, and last week, I did a circumnavigation with my Citation-X, and ran my system for hours at a time, and did not notice a fps slow up until I arrived a certain airports. KSFO is bad for me.

@V12: Off topic, but I thought you night know where does one post changes/additions to the nav.dat file? Casablanca Morocco is missing an important navaid, which I have added to my nav.dat. Had to stop there. Wanted to "have a drink" at Rick's Place, and land at the airport where the final scene took place.
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Re: Low Framerate

Postby Robertfm » Thu Nov 07, 2019 12:02 pm

SurferTim wrote in Thu Nov 07, 2019 11:16 am:
Robertfm wrote in Thu Nov 07, 2019 8:51 am:Forgive me if my paraphrase is wrong, 'so you are saying it's the Sim not my system.' So why did I initially receive 120+fpm in game. It has settled back to 60 but drops to less than 30 after several hours flying.

At the risk of repeating myself, that sounds like a heat problem. If it were my system, I would take the case side cover off and get a small fan to circulate air inside the case, just as a test.

Edit: As I recall, you use Windows 10. There should be utilities available to monitor CPU load and temp.



Have software that is monitoring the CPU & GPU and neither is going above 40 degrees well below it's maximum acceptable temperature according to the Specs.
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Re: Low Framerate

Postby V12 » Thu Nov 07, 2019 1:08 pm

SurferTim wrote in Thu Nov 07, 2019 11:44 am:@V12: Off topic, but I thought you night know where does one post changes/additions to the nav.dat file?

Check PM.
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