Severe loss of FPS when calling GSX in P3D v4.5 + Hotfix 1

[wiss]

Hello everybody

I have a problem with P3D v4.5 + Hotfix. It happens to me that I suffer a severe loss of FPS when activating GSX for doing a pushback. My version of GSX is 2.6.0.0.

It can happen with different planes, such as the QW787, the Aerosoft and FSLabs Airbuses, or any PMDG aircraft. Also, it tends to happen more when using more complex sceneries, such as FlyTampa, Aerosoft or FSDreamTeam ones. It almost doesn't happen when flying from default sceneries.

For example, I can be setting up a flight with the QW787 in the ImagineSim KATL (the latest version). Before calling GSX, I can easily have 60 FPS (which are locked internally by P3D), but after calling it, it can drop to 10. Even after finishing the pushback, with all the GSX objects disappearing, the FPS stay at roughly 10.

The weird thing is, that some time after, when I'm airborne, the FPS fix themselves at any random moment and go all the way up to 60 again. This can happen in any part of the world, so this fix is not caused due to, for example, flying in less complex scenery. Also, I verified that this fix is not caused by flying from a clouded area to a cloudless one. I can be in an area with very dense cloud coverage when this fix occurs.

It also happened a few times that when activating GSX after landing, the problem reoccurs.

My P3D settings are medium/high. I have an i9-9900K CPU, 32 GB of RAM and a GTX 1660 Ti with 6 GB of VRAM. The GPU drivers are up to date. I don't use Nvidia Inspector. I use add-ons such as ActiveSky for P3D v4, REX SkyForce and Environment Force.

Any ideas? Thanks

[Captain Kevin]

Just taking a shot in the dark, but what happens if you don't use REX Environment Force. Only asking because I know that particular one has caused issues with add-ons before, and I don't know if those issues ever got resolved.

[Farlis]

It' can't be REX because I suffer from those drops as well and I don't use REX.

[XCLTM3]

I can confirm I see this in my P3Dv4.5 also.

Take note that you should also see it when calling up the ATC menu for the first time within P3D - if you haven't checked yet - try it and see what result you get. You should see a significant drop for a second or two - then a return to normal frames.

I did raise this some time back in the P3D forums.

[virtuali]

The weak GPU and specifically the not so high VRAM is likely your problem, which seems to be confirmed by your observation that you don't have much issues with default airports and I'm sure you would see zero issues on default airports + default airplanes.

You must understand that VRAM is not "infinite" resource. If your VRAM is *already* close to exhaustion because of your scenery + airplane + weather add-on, it's possible the added objects from GSX could simply be enough to go from "close to exhaustion" to "exhaustion". The thing is, when VRAM is not enough, the drop of fps is DRAMATIC and sharp, it's not a gentle reduction.

Now that you cannot realistically exhaust system RAM with 64 bit software anymore, the new bottleneck to be aware of is VRAM.

Of course, it's easy to pub blame on GSX, just because you called it last, when the rest of VRAM memory-consuming stuff (airport, airplane, background scenery, weather engine clouds, AI ) was *already* loaded and might have been barely able to it the card VRAM. Adding a bit more, and you cross the threshold between being able to fit everything in VRAM or not, which will cause the sharp drop in fps.

Your system is not very balanced, because you have an insanely good CPU, enough system RAM, but with an average GPU with not so much VRAM ( some entry level cards have 8GB ), so your CPU is wasting cycles just to wait for the video card to finish its job and, the moment you exhaust VRAM, fps will collapse.

I'm sure a better GPU with more VRAM, like the 1080ti, which is still the best card ever made by nVidia or the new Radeon VII with 16GB, will do wonders with your system.

In any case, here's a video I just made, show ZERO fps loss by GSX Pushback:

The place it's FSDT KIAH, with the PMDG 737, with Ultimate Traffic Live at 100% density. The PC it's a stock i7-6700 (4 years old CPU), with 32GB and an nVidia 1080 Ti 11GB.

Note there's a small fps drop at about 1:00 minute, but that was caused by having used 4x time acceleration because I didn't want to wait too much for the APU to start, so it doesn't count.

As you can see, I also purposely panned the view several times, both to show the high number of AI, and to show GSX doesn't cause ANY stuttering, not even while it's pushing, and 100% AI is the most demanding situation which could lead to some stuttering. But there wasn't any here.

It's clear that GSX doesn't have any visible fps effect per se, even when used with a detailed add-on airport, with heavy traffic and with a detailed airplane add-on but, of course, depending on your system, you might have to adjust some of the settings.

The settings that affects VRAM consumption the most are:

- The overall resolution. I use 2560x1440.

- The overall max texture size. I set it at 4K, because with 11GB of VRAM, it's no big deal

- The antialiasing settings. I never set this too high, 2x with FSAA it's enough for me

- The shadow quality. Mine was set to maximum.

[Farlis]

Well in my case updating the GPU is out of the question. I just bought the 1660TI last month. I would have gone for the 1080TI but it is not available anymore. I settled for a medium card because I don't use 4K resolutions and from the tests I read it was said it was the best card one could get if one is staying at FullHD. Everything above it would be just shelling out money for headroom that is never going to be used at resolutions lower than 4K

[virtuali]

I would have gone for the 1080TI but it is not available anymore

The new Radeon VII has roughly the same performance, with 16GB of VRAM, and it's a 2019 card.

I settled for a medium card because I don't use 4K resolutions and from the tests I read it was said it was the best card one could get if one is staying at FullHD. Everything above it would be just shelling out money for headroom that is never going to be used at resolutions lower than 4K

It's not clear from your message if you *do* fps issues or not when using GSX, like the OP. If you do, I already listed all the various things that can affect VRAM consumption and fps. It's not entirely true lots of VRAM is only required for 4K resolution. It depends on your settings as well.

For example, some of the higher antialiasing modes renders internally at much higher resolution of the one actually in use, thus consuming high amounts of VRAM even in Full HD.

[Farlis]

"The new Radeon VII has roughly the same performance, with 16GB of VRAM, and it's a 2019 card."
 
I will not spend more money on a GPU than for the combination of a Motherboard and a CPU.

[virtuali]

I will not spend more money on a GPU than for the combination of a Motherboard and a CPU.

You don't have to change the motherboard, just to get a new video card. And if you don't, then just tone down your settings. That's why settings are for.

[Farlis]

I just thought I should give a little update on the situation.
I never quite got around to solving the problem, when my old Quadcore CPU solved the problem for me by dying from years of prolonged overclocking.
So I had to bite the bullet and update Mainboard, CPU (A Ryzen 7 3700x this time) and RAM, since my old hardware was not upgradable with current components any more.

Now the performance problems when calling GSX in certain highmemory situations are gone. So in this case it was not the GPU or the lack of VRAM, but simply my old CPU reaching its limits.

So maybe you might want to consider adding a minimum CPU specification in the System Requirements for GSX?

[virtuali]

So maybe you might want to consider adding a minimum CPU specification in the System Requirements for GSX?

There are no specific CPU requirements for GSX, my CPU is 5 years old ( i7-6700 ) and works just fine with no fps loss when calling GSX and, since GSX is available in TRIAL VERSION, what's better than allowing users to test it on their own system with their own settings ?

when my old Quadcore CPU solved the problem for me by dying from years of prolonged overclocking.

That was perhaps the problem. Were you using a proper cooling system ? If you just overclock without enough care about thermal issues, your CPU might start throttling down to safe itself from burning, thus REDUCING performances.

So in this case it was not the GPU or the lack of VRAM, but simply my old CPU reaching its limits.

My suggestion about changing GPU was in reply to the OP, which had an i9-9990K with a 1660Ti, and that still's valid and today, with P3D V5 more reliance on the GPU and on the amount of VRAM available, it's even more valid than ever. That CPU *screams* to use a 2080Ti.

You never said which CPU you had but the problem was never a supposedly CPU-hungry GSX, it was your CPU close to failing and, having likely had to reinstall Windows from scratch after a complete CPU+mainboard chnage, I guess most of the issues you were having, which were never caused by GSX in the first place, were simply fixed by a system reinstall.

[Farlis]

There was no need to reinstall Windows when I upgraded the Motherboard and CPU.
I don't understand were people get the notion this would be unavoidable.
Changing these components is just as Plug and Play as everything else under Windows. The only thing you have to do is update the Windows Product-Key registration to your new setup. But that is just one click and it is done.