I have done a back-to-back comparison of the iFly 737-800 in both FSX and Prepar3D v2.4, with the same add-ons (ORBX), at the same airfield (Barkston Heath AB in the UK) and I must confess I am very disappointed with the frame rates in P3D. Whereas I can achieve approximately 38-40 FPS in FSX, I am only really getting half of this at 18FPS in P3D. This to me is almost a show-stopper for serious use of P3D with my current rig. I understand that FSX is predominantly CPU-based whereas P3D does allegedly make more use of GPU. Even turning the sliders down in P3D (as some have suggested) seems to have little effect in improving the situation.

 

I am using a GTX 970 graphics card which I would have thought would be more than adequate, short of major expenditure otherwise. My CPU is a little dated (an i7 875K with boost to 3.6 GHz), but the exercise with FSX suggests that the CPU is certainly up to it where CPU-dependency is concerned.

 

Is this typical of other peoples experiences of P3D, or are you faring better in this respect? The impression is that for serious P3D applications, a particularly capable rig is required with a CPU far in excess of my own perhaps meagre 3.6 GHz, despite the fact that P3D makes better use of the GPU. If this is the case then not all of us are prepared to venture into such expenditure merely for the sake of comparatively inexpensive flight simulation software. It is perhaps a pity that, in achieving what they have with P3D, Lockheed Martin has apparently sacrificed so much in the process, with what is essentially an improved version of FSX (and I cannot deny that they have progressed things very significantly), albeit for academic and professional use.

 

Your thoughts and suggestions here would be most welcome, and I most certainly do not want to ditch P3D completely at this stage on account of its poor performance relative to FSX, in terms of FPS.

 

 

 

Paul Hermon

Hi there,

 

I used to have performance issues as well and it took quite a while to collect and try the various tweaks that are supposed to improve performance. In the end it boiled down to this:

- Reduce textures to 1024 resolution - reduces blurries and possibly the risk of OOM

- Reduce cloud shadows to 10km

- Turn off all car and ship traffic  > this does not increase the framerates terribly much, but it does help to make P3D run considerably smoother

- Tweaks in P3D.cfg: Add FIBER_FRAME_TIME_FRACTION=0.01 as suggested here; and TEXTURE_BANDWIDTH_MULT=160 (details here)  > these tweaks can increase performance considerably

 

Of course tweaking is very individual so your results may vary greatly! But with the above tweaks I am able to run P3D on high or even very high settings on my so-so hardware (i5-750 3.4 GHz, GTX770) without any performance issues, even in large airports. I don't have the iFly but with your hardware it should definetly be possble to get P3D to run at least as smooth as FSX.

 

Cheers,

Steve

But most of all, try using

 

[bufferPools]

UsePools=0

RejectThreshold=131072

 

....in your FSX.CFG.    I think this could yield great benefits on your system because it passes more processing from the CPU to the GPU, and you have a considerably beefier GPU than you have CPU.

I tried the iFly NGX for P3D and had the same results. Even at cruise altitude I was lucky to get 25FPS. I7 [email protected], GTX770. I returned it for a refund. The only other aircraft that rivaled it for poor performance is the CS777.

 

Your thoughts and suggestions here would be most welcome, and I most certainly do not want to ditch P3D completely at this stage on account of its poor performance relative to FSX, in terms of FPS.

 

Paul Hermon

 

Don't think it's P3D as we looked at this in the past. I ran a few tests as did others and got the same results like something is limiting the frames to 20 in P3D from select FSX port overs.

 

http://forum.avsim.net/topic/439558-ifly-737-for-prepar3d-v22/?p=3060591

 

IFLY VER 3.2.1

PMDG 737 1.0

 

P3D 2.3

 

FSX

      IFLY        49+/- FPS

      PMDG     45+/-FPS

      Phenom  52+/- FPS

 

P3D

      IFLY         23+/- FPS

      PMDG     25+/- FPS

      Phenom   53+/- FPS

Vincent,

               I think this is part of the problem with this aircraft. It's a straight port over from FSX with no optimization for P3D. Then they charge $79 to boot. 

I have tried the various tweaks as suggested but there is no significant improvement. I am beginning to think that a lack of optimisation for P3D may be, in part, the issue with a number of products which are themselves marketed as P3D versions but may possibly be, as Mike W has put it, straight ports over from FSX.

 

Whether or not we shall see any upheavals of certain products to improve their performance in P3D remains to be seen, but I suspect for a lot of us we may have to continue to use FSX to enjoy something better than a slide show.

 

Thanks for all your inputs thus far. 

Thank goodness I'm not alone. My dated 2500K at 4 ghz (OC is dying week by week used to be at 4.4 ghz) just does not cut it. I'm suprised to hear it's not great with a gtx 970 either. My plan was to upgrade in hopes to increase fps. Previous versions sure seemed to ear up more GPU but 2.4 seems to have gone back to cpu usage focus. Maybe it's just my thoughts though.

 

I agree on about half the fps - I really have gone back to FSX and am considering the GTN 750 for FSX now...

There should be a balance between the power of CPU and GPU. It doens't work to pair an old CPU with a powerful GPU or vice versa.

 

The comparision FSX/P3D v2 should be on the first hand with the same standard aircraft. On the second hand one can do it with a non standard airplane which has a well done version for P3D v2 too.

 

To do only one flight here and another one there is also a non professionall method and doesn't say anything.

Spirit

 

 

its poor performance relative to FSX, in terms of FPS.

 

Paul many people new to P3D concentrate on fps as this was uppermost in their mind when using FSX.  Many P3D users turn off the fps counter and instead concentrate on the smoothness and enhanced reality of the sim.  Try that for a while.   <_<

 

I grant you anything under 20fps is noticeable however.  :(

 

 

I grant you anything under 20fps is noticeable however.

 

But a constant 20+ can be like silk!

 

 

But a constant 20+ can be like silk!

 

It wasn't for me. For what they were charging, they could have put some effort into it and reworked it for P3D. The saving grace is Flight1's refund policy.

It wasn't for me. For what they were charging, they could have put some effort into it and reworked it for P3D. The saving grace is Flight1's refund policy.

Then you didn't have a CONSTANT 20+. 

 

I've had flights where it was 60, 35, 65, 30, etc etc. - THAT is stutters.

 

If you can get your system set up so that whatever you cap your FPS at is CONSTANT - you are good to go, be it 20 or 40.

 

I'm playing around wit settings a bit now so I have mine capped at 33 - most of the time it's fine but there are situations when it starts fluctuating and I am not getting the smooth operation I do at 20.

 

Vic

I am running it unlimited fps and it is a great surprice without stutter.reałly smooth on my system.In the Carenado default i am at 50-60 fps most of the time in ORBX FTX NZSI region. Flytampa EKCH about 40-45fps. Cant really complain with that.

 

Michael Moe with old 344.11 drivers

What helped most for me was setting FPS to unlimited.