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Q_flyer

P3D2 and the Frame Rate Slider

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This has been mentioned here and there in other threads but I just wanted to underline the point.

 

I can't speak for every user, but for me (and I suspect other ATI users at least), the Frame Rate Slider (lock) in P3D has a dramatic effect on FPS.

 

Setting any value at all (but especially lower values like 30) really dramatically reduces frame rates for me.       Setting UNLIMITED adds about 50% to FPS.

 

Eg..... Majestic Q400, in heavy weather with medium settings, in a payware airport:-

 

  • With FPS locked in P3D at 30:    Average FPS = 24.9
  • With FPS locked in P3D at 24:    Average FPS = 21.5
  • With FPS locked in P3D at 60:    Average FPS = 26
  • With FPS set to UNLIMITED:       Average FPS = 41.9

 

As well as the FPS results themselves that you see here, P3D is also very stuttery when the FPS are locked, and buttery smooth when unlocked. 

 

If when you first try P3D you get poor FPS and performance, I'd recommend the first thing you do is try the sim with the Frame Rates set to Unlimited.

 

Happy flying!

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That darn thing sucks.

 

Seriously.

 

In the AXE earlier I was bouncing around 90 or so with it unlimited/no vsync/no TB. I set it to 60 and FPS dropped to 40.

 

Yet 45 gave me...45.

 

It's nice to see that it's as reliable as ever.

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I never had the FPS limited in FSX... I always had it unlimited! It's always better for me... Limited are problems...

 

 

Enviado desde mi iPhone 5S con Tapatalk

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I bet we'd get better results with a way of externally limiting FPS.....  I'm not sure if you nVidia folk can do that in NI, but as far as I know, us ATI people can't externally lock at present.      I used to use AntiLag which was brilliant, but obviously it was only DX9 compatible.

 

I'm not sure if RadeonPro limiter will work with DX11 but I'm not a fac of that program anyway as I find it a bit bloaty.

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I was always under the impression that with a higher frame rate, the system will reduce the image quality in order to achieve the higher rate.  Is this not the case?

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If it's anything like FSX, image quality is not reduced, just the susceptibility to blurries and popping autogen. For the past year I have reverted my FSX config back to unlimited with great results with little to no blurries and solid fps. I never really understood why the internal limiter affects fps so much and would love a proper explanation.  

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I never had the FPS limited in FSX... I always had it unlimited! It's always better for me... Limited are problems...

 

 

Enviado desde mi iPhone 5S con Tapatalk

 

Could well be but this is P3D 2.0 and not FSX… ^_^ Don't think too quick that what worked for FSX will work for P3D 2.0! I sure am going to give it a try (although I am also used to limiting it).

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Dave,

 

first and foremost, why did you change the fantastic Dexter pic, I love Dexter ;-)

 

Just an FYI, although I can't notice any difference using NI, however, apparently the external FPS limiter works just fine. Will have to do more testing on textures, blurries etc. with the external limiter.

 

Thanks for the suggestion Dave!

 

Cheers,

Pete

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Changing FPS slider and resetarting the sim is causing revert to unlimited. is this normal? I have have to set it every time.

 

Edit: Strike that. Brain fart

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In FSX you could balance limiting the Frame rate with performance by dropping fiber frame time fraction to .10 vs. default .33.

 

I don't know if that even applies anymore.

 

But if unlimited works with no side effects the I don't see a reason to even bother limiting. In FSX it could cause stuttering and blurries.

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I find the FPS limiter to be situational.

 

In heavy load situations, there's no question that using the slider at unlimited yields higher frame rates, and it seems to do so while balancing the load properly - i.e. if you're only getting 28 fps with the slider set to unlimited, it's still a very smooth 28 fps, with no evidence of the fact that its under a heavy workload other than the visual presence of the reduced frame rate counter.

 

However, I have found examples of when you're not under heavy load, in the middle of nowhere with light weather and nothing around, where the fps starts to get very high (90+fps for me) and then it starts to 'bounce' a bit, shooting up and down by 25% or so, and this causes (for me) stuttering behavior.  Setting the slider to limit the frame rates in these situations makes that issue go away completely (for me).

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One must balance higher frame rates with smooth operation by limiting CPU cycles with a locked setting..

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What someone from LM told us to do was to set, in P3Dv2

 

1) VSync 1/2

2) tripple buffering

3) FPS limiter set 10% above previous fixed value. If you were using 30, set it at 33...

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 Whats Vsync 1/2?

 

I think he simply meant half of your monitor's refresh rate. If yours is 60, set P3D to half of it = 30 + 10% = 33. There isn't an option that says '1/2 refresh rate' like in NI.

 

Some other are saying unlimited works better for them. Not so much has changed since FSX... ^_^

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What is different is that setting frames to unlimited actually seems to help eliminate the blurries (which is the opposite to everything we learnt with FSX)... 

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I think he simply meant half of your monitor's refresh rate. If yours is 60, set P3D to half of it = 30 + 10% = 33. There isn't an option that says '1/2 refresh rate' like in NI.

 

Some other are saying unlimited works better for them. Not so much has changed since FSX... ^_^

In Prepar3D, the "Triple-Buffering" is the equivalent of 1/2 refresh rate, or so I've been told...

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Only if LM are redefining established terms ! (which I guess they probably could  :lol: )

 

Simple explanation - TB allows vsync to be used without having to worry about the frame rate dropping below refresh, and going straight from 60 to 30, as would happen with double buffered vsync. It does introduce input lag as a consequence of the extra buffer.

 

In many engines a good way to have your cake and eat it too is to use TB/Vsync, and then set a frame limiter to refresh -1.

 

This fails miserably with the flightsims  :huh:

 

EDIT: Testing some stuff now, just wanted to add, it is hilariously easy to max out even a decent GPU with this engine. 

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I had a look at how performance was at Unlimited and I have the idea things are a bit smoother, specially when looking around with TrackIR.

 

And btw I also think that, just as with the DX10 fixer, it also helpt to set the TrackIR process at High priority! I only thought about it this evening, tried it and it seems to have a positive effect. Looking around without TIR at that priority and the slider at unlimited results in a slightly smoother experience. However, it is very hard to really test this...

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The only issue I have with unlimited in practice is generating 150 fps in the cruise.

 

It's just a different ballgame. in FSX I had to force 3D clocks to keep my cards awake. 

 

Testing now, Internal cast and receive eats up 25-30% GPU time on low.

 

No surprise that the shadows, all of them, are by far the biggest GPU killers.

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it's a known issue , you don't need to feel bad.

I had it since FSX. every time you limit with the Sim the FPS, it drops drastically lower.

it was confirmed by many this behavior at the time, I was hoping with P3Dv2 it would be solved, but apparently it wasn't

that is why I never limit my FPS via the Sim, only via the driver.

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P3D2 and the Framerate Slider

 

That sounds like the start of a book series. When can we expect the sequel....P3D2 and the VAS Calculator?

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it's a known issue , you don't need to feel bad.

I had it since FSX. every time you limit with the Sim the FPS, it drops drastically lower.

it was confirmed by many this behavior at the time, I was hoping with P3Dv2 it would be solved, but apparently it wasn't

that is why I never limit my FPS via the Sim, only via the driver.

 

It's a consequence of the engine.

 

To fix the FPS drop when using the internal limiter you need to set Fiber Frame Time Fraction to .10 or .15. This will bring performance back up to or near what you get unlimited.

 

BUT, in FSX this would raise the chance of blurries and texture loading problems. This same tweak can still be made in P3D2 so it can't hurt to try.

 

I ran .10 in FSX with little negative effects but some got bad results. It just depends. 

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