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Jimmy RFR

XP11: Framerates, window glass, & VSync

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So last night I was sitting doing a few things in and out of the vFlyteAir Traveler, at one of my gateway airports in the middle of the prairies - seriously in the middle of nowhere, so not demanding at all in regards to computer performance. But I was noticing that my framerate was wildly fluctuating when switching the camera viewpoint from inside to outside the cockpit - 60fps outside, to 30fps inside. This was with VSync turned on.

 

So I started playing around with settings a bit and discovered a few things.

 

#1. VSync being on hits the system hard, and interestingly enough, it seems to cause a spike in CPU usage, not GPU usage.

 

#2. Glass, or viewing through glass, causes a massive fps hit with Vsync active (less with VSync off) I tested this with multiple aircraft, all ones where you can view the outside scenery almost completely through the glass (no window frame taking up part of the view), while allowing for the canopy to open completely so as to view the same scene with out glass. Alternatively, the Traveler has a 'hide glass' button, which provides the same function. In every case, hiding the glass (or opening the canopy and viewing the same scenery) allowed for vastly improved framerates.

 

Some example screens regarding glass visibility and framerate variation (again, these findings were mirrored in other aircraft, the Traveler isn't the culprit, it's just super easy to hide the glass):

 

XP Settings:

6kAj7zD.jpg

 

VSync On, Glass On (33 fps):

pTEQtlX.jpg

 

VSync On, Glass Off (55 fps):

D62Vg0j.jpg

 

VSync Off, Glass On (50 fps):

se9kv8t.jpg

 

VSync Off, Glass Off (57 fps):

AU5QKgu.jpg

 

So.. can anyone shed some light on what is going on here? This shouldn't really be such a noticeable thing, should it? Anyone care to try and replicate?

 

Also - it's important to note that the default 172 had no appreciable difference, high frames (in the 50's, same parking spot), but you can't really see it's glass from the inside, either.

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In XP10 the glass works, but I don't think it does in XP11 and i love this aircraft. Love the sound but there is a looping audio at high rpm

 

BTW I think I feel the ADF not working ?

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Love the sound but there is a looping audio at high rpm

BTW I think I feel the ADF not working ?

 

Have you posted these issues in our forum already? If not, please do, because I want to do support only at one place, to not get lost. Besides, we should not capture this thread.

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Have you posted these issues in our forum already? If not, please do, because I want to do support only at one place, to not get lost. Besides, we should not capture this thread.

 

Right on sir.

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Does the glass show visible real-time reflections?

 

I do know the gauge glass shows visible reflections; I've never checked to see if they're real time. I can't tell on the cockpit glass, it's simply a bit darker with it present. Even so - my reflection detail is turned to minimum as that slider carries with it a framerate drop with little benefit, unless you are near water of course.

 

That said, I do know from admiring PBR effects on aircraft with it, that real-time reflections on say, a fuselage, do not have an associated framerate drop (nor do they seem to be affected by the reflection slider).

 

The other interesting aspect is that in the case of the above screenshots, if I zoom in on the instrument panel, so that primarily gauges fill the screen, turning on and off the glass has the same drastic change in framerates. This is not something I can check on other aircraft, since you need to be able to turn the glass off to check.

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Just an update regarding PB8: This issue, for the most part, has completely went away. The following screenshot is the very same scene and settings as the one above where I recorded 33 fps:

 

XEsISLZ.jpg

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Hi,

 

I have an only slightly worse system to yours (not overclocked though and a 970 (4 GB) instead of a 980Ti). I use similar settings and get 18 fps sitting in the C172 on a runway at EDDT. In Prepar3d3 I can maintain 30 fps nearly throughout even at busy airport addons like FB KFSO.

 

I tried the threading setting without any noticeable result. Deleted preferences for Beta8 and built new ones. This is with HT off, CPU is running around 40 %, GPU between 80 and 100.CPU usage is even worse with HT on. 

 

Default scenery, no addons yet. Now tell me where to start debugging. We're not speaking about 5 % but roughly 50 %. XP10 does not run much better, btw.

 

Kind regards, Michael

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After writing theses lines I had an idea. Instead of the second (widescreen) monitor which I'm usually using for simming (the one in the sig) I started XP11 in my "normal" (1920x1080) monitor which I use for ordinary work. Guess what - I get the same frame rates in the mid-30s as the OP enjoys.

 

Now I have to investigate the cause for this, maybe it's the different connection, the lower monitor fps setting (the flightsim monitor is set to 30 fps, the work monitor to 60 fps) or even something else.

 

Anyway, it's nothing to do with XP11, my machine or even a bad XP setting from my side.

 

Sometimes writing a contribution makes your own brain work...

 

Kind regards, Michael

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GPU between 80 and 100.

 

After writing theses lines I had an idea. Instead of the second (widescreen) monitor which I'm usually using for simming (the one in the sig) I started XP11 in my "normal" (1920x1080) monitor which I use for ordinary work. Guess what - I get the same frame rates in the mid-30s as the OP enjoys.

 

I think in your case, you've discovered the cause of your low fps - the fact that you were getting 18 fps on a 3440x1440 monitor with 80 - 100% gpu usage & low cpu usage, means that at that resolution, you were hitting a hard limit on what your 970 is capable of. When you switched to 1920x1080, your fps went up... clearly indicating that now your GPU was able to keep up at the lower resolution.

 

I personally think that ou really can't compare P3D and XP in terms of what you can expect your framerate to be. You can of course compare the final result - as in, which one gives better performance for you in the end - but there really is no equivalence to be found in scenery or settings that can enable you to point to one and say "hey, I can get XX fps in P3D in this location, why can't I in XP?"

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After some research, I am afraid you are right, Jim. I changed monitor frequency, cable/interface ... all the same. Only when I lower the resolution on the flight sim monitor from 3440x1440 to 2560x1080 I get framerates in the low 20's which I consider sufficient.

 

I am still disappointed, though. The GTX 970 (and this is a factory overclocked EVGA, no el cheapo) isn't an outdated card and gives excellent performance under Prepar3d and AeroflyFS2. With ~2.1 GB textures (from the 4 GB) I should be far from that dangerous "slow" area either. I doubt I can afford a Titan III in the foreseeable future.

 

And this is without W2XP and more fancy stuff, yet.

 

Thanks for your help, anyway you are right - unfortunately.

Michael

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After some research, I am afraid you are right, Jim. I changed monitor frequency, cable/interface ... all the same. Only when I lower the resolution on the flight sim monitor from 3440x1440 to 2560x1080 I get framerates in the low 20's which I consider sufficient.

 

I am still disappointed, though. The GTX 970 (and this is a factory overclocked EVGA, no el cheapo) isn't an outdated card and gives excellent performance under Prepar3d and AeroflyFS2. With ~2.1 GB textures (from the 4 GB) I should be far from that dangerous "slow" area either. I doubt I can afford a Titan III in the foreseeable future.

 

And this is without W2XP and more fancy stuff, yet.

 

Thanks for your help, anyway you are right - unfortunately.

Michael

 

Bonjour,

 

I am new to X-PLANE 11 beta, and I too find that a high resolution (I use DSR) has a big impact on performance.

I have a 4790K OC 4.7 GHZ, and no problem with the CPU but my GPU a GTX1080, is at 100% utilisation with bad FPS if I push the settings.

I also notice strange behavior. By panning only very few degrees (horizontal and vertical) in virtual cockpit. The FPS can vary from 50 to 12.... Even if there is nothing terrific to display (the pilot seat for example  :smile: )

 

So, also we must rember that it is a beta version.

Cheers

Claude

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