Clouds tank framerate

[19dcavscout 39]

Hi all. I am having some issues with overcast clouds. Whenever there are heavy clouds (typically overcast), my framerate tanks from 70+ to single digits until it finally hard reboots my system. I am positive the reboot is due to my power supply failing, and is in the process of being replaced (just waiting on slow APO shipping).

I have reduced cloud layers in AS4, reduced AA, reduced the cloud texture sizes, all to no avail. I did a fresh reinstall of 4.1 (it was doing this in 4.0 as well), and I cannot figure out what I am doing wrong. This can happen in any aircraft that I am flying. The frames mentioned above are with the PMDG 777.

I have, what I think, a pretty good system and I really don't think it should be tanking that bad with the clouds. Here are the specs and what I am running.

CPU: i7-4790k O/C 4.7GHz
GPU: EVGA 1080ti Founders
RAM: 16GB DDR3 RAM
HDD: 2x SSD and 1TB HDD

Addons:
ORBX Global/LC/Vector
AS4 w/ ASCA + ENVTEX +  ENVSHADE
Various aircraft.

Not sure what else I can do. Thanks.

[exeodus 78]

Are you using Nvidia Inspector to enable Sparse Grid Supersampling AA?  If so that will definitely tank your FPS in heavy cloud cover.

 

[Bob Scott 7,720]

SSAA or externally-enabled SGSS anti-aliasing will hit frame rates.  But given what's going on in your system, it could be (probably is) a side-effect of the power deficiency.

I have to ask the obvious, too...you do have power cables connected to the GPU power connectors on the video card?  I've helped a few people along the way that plugged in a GPU and forgot/missed/didn't know about connecting the additional power cables from the PSU to the graphics card, and that would cause exactly the sort of issue you're seeing.  Also, depending on the PSU, if it has multiple 12v rails and several power cables connected to each rail, if both GPU power cables are coming off the same rail, you could be overloading one of them...in that case switching one of the GPU power cables to a different one would help.  If it's a single-rail supply, that probably won't help (although if a cable/connector is bad it still could).  And definitely make sure the GPU connectors are not coming off a common cable, either daisy-chained off a single cable or using a cable-splitter on the end of the GPU power cable. 

Waiting on APO...been there, done that (three overseas tours in my 27 years in the USAF).  The slow boat to china never moves slower than when you really need something. ;-)

Regards

 

[downscc 1,327]

I found that using a frame rate limit would significantly improve the lowest frame rate that I would get around certain types of cloud (overcast/undercast).  You don't need a high frame rate (it isn't a shooter game), many configurations will work just fine (smooth animation and no stutter) at rates as low as 20.  I noticed the frame rate hit into the low teens went completely away, no frame rate hit, when I set a limit below 26 fps.

[orangina 1]

Just to explore another possible tips, try to disable cloud shadows. If it helps, try to modify this in prepar3D.cfg:

OPAQUE_SHADOW_TEXTURE_SIZE=2048
TRANSLUCENT_SHADOW_TEXTURE_SIZE=512
OPAQUE_SHADOW_DRAW_DISTANCE=2000
TRANSLUCENT_SHAD0W_DRAW_DISTANCE=2000

It helps in my case, when my FPS drops down at sunset for example.

 

[19dcavscout 39]

20 hours ago, exeodus said:

Are you using Nvidia Inspector to enable Sparse Grid Supersampling AA?  If so that will definitely tank your FPS in heavy cloud cover.

 

I am not. I even reset Nvidia Inspector to default settings.

19 hours ago, w6kd said:

SSAA or externally-enabled SGSS anti-aliasing will hit frame rates.  But given what's going on in your system, it could be (probably is) a side-effect of the power deficiency.

I have to ask the obvious, too...you do have power cables connected to the GPU power connectors on the video card?  I've helped a few people along the way that plugged in a GPU and forgot/missed/didn't know about connecting the additional power cables from the PSU to the graphics card, and that would cause exactly the sort of issue you're seeing.  Also, depending on the PSU, if it has multiple 12v rails and several power cables connected to each rail, if both GPU power cables are coming off the same rail, you could be overloading one of them...in that case switching one of the GPU power cables to a different one would help.  If it's a single-rail supply, that probably won't help (although if a cable/connector is bad it still could).  And definitely make sure the GPU connectors are not coming off a common cable, either daisy-chained off a single cable or using a cable-splitter on the end of the GPU power cable. 

Waiting on APO...been there, done that (three overseas tours in my 27 years in the USAF).  The slow boat to china never moves slower than when you really need something. ;-)

Regards

 

I will double check the power cables and will see if that helps at all. Thank you! I never thought to check that. 

17 hours ago, downscc said:

I found that using a frame rate limit would significantly improve the lowest frame rate that I would get around certain types of cloud (overcast/undercast).  You don't need a high frame rate (it isn't a shooter game), many configurations will work just fine (smooth animation and no stutter) at rates as low as 20.  I noticed the frame rate hit into the low teens went completely away, no frame rate hit, when I set a limit below 26 fps.

Definitely will try this thank you.

17 hours ago, orangina said:

Just to explore another possible tips, try to disable cloud shadows. If it helps, try to modify this in prepar3D.cfg:

OPAQUE_SHADOW_TEXTURE_SIZE=2048
TRANSLUCENT_SHADOW_TEXTURE_SIZE=512
OPAQUE_SHADOW_DRAW_DISTANCE=2000
TRANSLUCENT_SHAD0W_DRAW_DISTANCE=2000

It helps in my case, when my FPS drops down at sunset for example.

 

I had upped the resolution to get smoother looking shadows in the VC. I never thought it could be the cloud shadows. Definitely trying this. Thank you!

[AnkH 2,262]

I honestly do not know why people always opt for a new PSU if they experience hard reboots and yet they use an overclocked CPU... Before I would go down this route I would definitely try a slightly reduced OC or even no OC at all. Might be that the 4.7GHz are simply not stable under full load conditions, no? Then even a 10'000W monster PSU will help nothing...

BTW: the power decrease over time followed by the hard reboot further supports this. Did you ever monitor CPU and GPU temp levels? It sounds more like throttling. A hard reboot due to the PSU usually takes place spontaneously and all of the sudden, no decrease in FPS observable...

[Bob Scott 7,720]

2 hours ago, AnkH said:

I honestly do not know why people always opt for a new PSU if they experience hard reboots and yet they use an overclocked CPU... Before I would go down this route I would definitely try a slightly reduced OC or even no OC at all. Might be that the 4.7GHz are simply not stable under full load conditions, no? Then even a 10'000W monster PSU will help nothing...

BTW: the power decrease over time followed by the hard reboot further supports this. Did you ever monitor CPU and GPU temp levels? It sounds more like throttling. A hard reboot due to the PSU usually takes place spontaneously and all of the sudden, no decrease in FPS observable...

I don't think this tracks very well.  The CPU is loaded up pretty much the same by P3D in good weather or bad...if the overclock is unstable, it would be also be unstable in conditions other than heavy clouds.

A severe drop in frame rate that consistently occurs when a graphics-intensive load is placed on the computer does suggest a GPU issue...and a GPU issue that repeatedly culminates in a reboot or non graphics specific blue-screen is consistent with severe voltage sag from an overloaded PSU, or possibly, as I described above, an overload on the PCIe bus power lines due to faulty or no aux power to the GPU.

One other suggestion would be to run the OCCT test utility to see if the same problems occur.  That test suite allows separate CPU and GPU load tests.

Regards

 

[AnkH 2,262]

Correct. Thanks for the clarification. However, the decrease in performance before the actual hard reset is puzzling me. Usually, insufficient power results in a sudden crash and reboot. Somehow, here the FPS start decreasing over time and only then the crash occurs. To me, this is indicative of some throttling events just before the crash. Badly overclocked GPU? Maybe even a defunct one?

Anyway, I would nevertheless first run some tests before I would go replacing the PSU...

[19dcavscout 39]

23 hours ago, AnkH said:

I honestly do not know why people always opt for a new PSU if they experience hard reboots and yet they use an overclocked CPU... Before I would go down this route I would definitely try a slightly reduced OC or even no OC at all. Might be that the 4.7GHz are simply not stable under full load conditions, no? Then even a 10'000W monster PSU will help nothing...

BTW: the power decrease over time followed by the hard reboot further supports this. Did you ever monitor CPU and GPU temp levels? It sounds more like throttling. A hard reboot due to the PSU usually takes place spontaneously and all of the sudden, no decrease in FPS observable...

The OC is stable and has been for years. I did another stress test on the system a week ago to see if that was the problem. The PC ran both CPUID's CPU-Z stress test and Heaven 4.0 test for 2 hours a piece with no issues. Temps for the CPU are in the 65-70C range for the package and never go above that. GPU stays in the 60's while running P3D due to the aggressive fan profile used, (It's a founders edition and they are known to temp out relatively quickly. I would rather deal with the noise). To further this that it is not the CPU, when looking at the clouds and my frames drop, the loads on the CPU consistently drop to 60% or so, showing that the processor is waiting for the 1080ti to catch up. Look away from the clouds and the GPU usage drops significantly and the CPU goes back up to 90-100% (As well as frames too). 

The PSU is 3 years old not and I sort of cheaped out on it back then. It says its a 750W, but I know that particular model has had issues with other people. I just couldn't pass up the $50 price tag. Plus I was running a 970 back then and the power requirements are not what they are now.