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kolaf

Complex aircraft, what to sacrifice to increase performance?

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Hi guys,

 

I'm running P3D 2.4 on a Intel 2700@ 4.5 GHz with a GTX 780 GPU. This allows me to have autogen density at thence, scenery complexity at very dense, cloud coverage at maximum at a distance of 90nm, shadows at medium with default values, and all the other sliders relatively high (except traffic which is around 15%).

 

Running on a 1080p monitor this allows me to look the frame rate relatively steady at 33 using the A2A C182 in FTX Norway in relatively cloudy weather. When I approach Oslo performance drops to around 20-25. If I uncap the frames (using the internal limiter) it jumps somewhere between 30 and 60 most of the time, but the simulation becomes a bit more stuttery.

 

If I'm running a more heavy add-on aircraft such as the iFLY 737 or MJC D8 I'm never able to maintain 33, it goes between 15 and 25 depending on how much ground and sky I see. I've attempted to improve performance for the complex aircraft both by reducing autogen by a notch and reducing shadow quality, but nothing seems to have any significant impact.

 

Which settings would be most beneficial for me to tweak to improve performance for tube liners? Also, according to what I'm reading in the forums I feel that I should be able to have better settings with my hardware with better performance.

 

Thanks.

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Try turning the tessalation settings down a bit and see if it works for you, it seemed to help me. If you're doing mainly IFR you probably don't need the mesh greater than 10m, or textures more than about 1m/60cm. Building and vegetation shadows are definitely a killer so disable them if they're on and see if they make a difference. I guess I run about medium to high settings on my machine - not that dissimilar to yours - and get around 30fps with the Aerosoft A320 but I run little to no autogen as I use almost entirely photoscenery. 

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In answer to the question on AvSim, "Complex aircraft, what to sacrifice to increase performance?"

by kolaf, Yesterday, 04:53 PM

 

The old man, ME, replied...

 

You know,

 

I may be about to totally reverse my flight simming flyosphy. I'm beginning to understand at the tender age of sixty-… Holy sh$t! ...-nine in five days??! ; That there is now and perhaps will be until I go to the big cursor in the sky, a fundamental truth.

 

And that truth is you can't have it all...

 

... and therefore you must compromise, and ask yourself two simple questions.

 

"What is it that you are flying; And, where are you going?"

 

You want performance in a complex tube-liner?...the Q-400, NGX, A-3xx, 767,t7,787???

 

...then you have to understand that you're probably;

 

1. going to be flying for pretty close to an hour, and;

2. most of that time is going to be above 20,000 feet

 

Therefore the VFR Eye-candy doesn't weigh as much as performance in the cockpit.

Therefore you should "de-rate" your eye-candy sliders...

you know which ones they are...

I won't repeat the obvious.

 

Conclusion...create and save setting #1 for that Visual/performance scenario.

 

Then, create a middle ground like the flights stipulated in Pilotedge's ratings tests...they rarely go above 20k ft, so eye candy is important, BUT...most of the exams are IFR, and frankly, you don't have time to "lookit the pretty butterflies"

 

Create and save setting #2 for that Visual/performance scenario.

 

Lastly, the other end needs not even be elucidated other than to say "VFR"...it's pretty much the opposite of the first case has no where near the demands of a Pilotedge rating exams Nor will you be flying an NGX OR ANYTHING LIKE IT......so lay back !

how about a silk scarf and A2a's PIPER CUB.....

 

Stick 'n rudder stuff...

 

Chop the throttle and get and stay way under 5,000 AGL... And

 

Enjoy the visual glories you bought with yer hard won bux!

 

..so, Create and save setting #3 for that Visual/performance scenario.

 

...and of the three settings.

 

stick with their purpose...and before you fire up your sim ask,

 

"What are you are flying; And, where are you going?"

 

Choose setup 1,2 or 3.

 

And JUST AVIATE....

Elevate yoursef'

 

And be thankful for the opportunity...

 

...BET YOU We will be doing A lot more flying , and a lot less tweaking…

 

… That's what I'm going to try for this coming year…call me a crazy old curmudgeon...

 

Keep the blue side up...

 

Happy new year!

 

Chas

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Thanks guys.

 

I am well aware of the need to compromise, I just didn't think it applied to me ;)

 

I guess my main question was what can I turn down which has the least impact on my experience and the highest impact on performance? I will try the suggested scenery objects shadows (I already have tessellation at high, not maximum, but I guess I could turn it down even further for IFR). With this and tweaking the autogen settings even lower I guess I should be able to create an IFR profile as mentioned above. Still, I want more eye candy in the VFR settings with better frame rate than I have now 0:-).

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The young guy, Chas ( I'm 78 in 3 weeks) hit the nail on the head.

 

quote name='kolaf' timestamp='1419932068' post='3145145']

I guess my main question was what can I turn down which has the least impact on my experience and the highest impact on performance?

 

AT FL20 or 30 you don't need detailed ground textures along route. Reduce them and performance goes up. Simple truth.

 

Vic

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Kill ai traffic and any cars or boats

 

Cloud draw to 60 mi

 

Drop autogen to dense

 

It sucks but that's what I've been doing

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I found that with P3D, cutting the densities (bldg and AG) did not create increased frames, rather smoothness. AI is a big killer for me but I don't fly the heavies so most of my visits are to smaller airports so I only put the default to  25% and GA to 100%. Very comfortable. I fly primarily ORBX (cuz I'm spoiled) and love the detail. VFR for me as you can see. As far as AC goes, I have to cut scenery even more if I am wanting to fly one with a glass cockpit. They really kill my performance, even the Carenado which on their earlier AC were very friendly. To me it's all about a fun aircraft with good visibility (337 I love) and great scenery. I will tell you that I love to fly XPX at dusk. It has such a look and feel to it, but as you know if falls short in many other areas. I think most of us just continue to try and make it better. We see a post that has a tweak and we are on it like stink on sh##. That's part of it. A new driver, a new tweek, a new cloud set or sky set. I try em all. It's just part of the fun.

 

Bob

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I dropped autogen to sparse and scenery complexity to dense, turned off all shadows except inside the cockpit and on the aircraft, and I still am not able to maintain 30 FPS. I have always thought but my platform handled relatively high settings quite well using simple aircraft, but I'm a bit surprised by the significant impact the iFLY 737 has on system performance.

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I'm a bit surprised by the significant impact the iFLY 737 has on system performance.

 

Why?  The iFly is a systems heavy aircraft just like the NGX.  Many people consider it to be second rate ... it is not.  Realism of operation costs performance,  regardless.

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Why?  The iFly is a systems heavy aircraft just like the NGX.  Many people consider it to be second rate ... it is not.  Realism of operation costs performance,  regardless.

I don't know, perhaps I'm just naive in expecting that my hardware would perform better than what I am seeing :-)

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expecting that my hardware would perform better

 

Your hardware is fine for FS9 and FSX.  Borderline for P3D.  I would advise you against purchasing, for instance, the CS777 for you will see frames in the single digits.  

 

Eye candy is fine for GA, though, like FSX, not convinced P3D is (yet) cut out for the tubes.

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Building density normal and turn SimObject shadows OFF and turn off any AI traffic.

 

Gets me about 4 fps with CS 777 (running 3840 x 2160) - worst case is 20 fps at complex airports with UT2 running ... but during flight it locked at 30 fps.

 

Cheers, Rob.

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I've attempted to improve performance for the complex aircraft both by reducing autogen by a notch and reducing shadow quality, but nothing seems to have any significant impact.

 

With FSX, one could adjust sliders and have a significant impact on frame rate in a much more proportional relationship, but less so now for sure w/ P3D.  Presumably this relates to how the GPU is utilized.   On day 1 of P3D V2.0 release I asked LM if they could comment on how sliders might predictably affect frame rate, and got no replies last time I checked.  

 

My sense is, P3D remains quite CPU limited, and is in fact more so than FSX was--and this is manifested most w/ complex aircraft.   I believe the way the rendering engine is designed steals some of the work the CPU could be supplying to manage a demanding complex aircraft and reserves this for pre-processing data that will be sent to the GPU.   The controls you have to play w/ in Display Settings in general are going to impact the GPU's role more, hence you don't see much improvement by changing the various settings in the context of complex aircraft.   This, I'm afraid, is an Achilles Heel of sorts for P3D V2.x.  And also, if this analysis is valid, then SLI will not be the salvation we hoped for.

 

All's not lost for sure--P3D's atmospherics in particular & autogen rending scheme are sufficiently impressive as to make the sim compelling even w/ its issues.   You just have to live w/in these limitations.  This means for example flying complex aircraft out of the lowest demand situations.  Forget about PMDG when it's legal & planes like CS777 out of anything but the lowest complexity airports.   Turning down sliders helps a little, but not enough to offset the demands CPU that are present in complex metro terminals AND complex aircraft in the same scenario.

 

My strategy is working well, which is to use high performance:complexity planes as much as possible.  For small planes, my machine can handle any airport in FTX regional scenery:  RA Turbine Duke & RA Lancair Legacy.   Since these are overall easy to manage planes on the CPU side or so they appear, and since they are flown at lower altitudes, it makes sense to turn up all eye candy and indeed I can.  I use QW757 & Super MD-80 for tubes currently:  even w/ these low-impact planes I still need to avoid FTX NCA & 3PD airports to have an ultra-smooth experience.   But no matter, w/ tube liners & FSCaptain involved, I don't have enough attention to devote to sightseeing during climb anyway, so it works quite well.  By the time I'm at cruise altitude, it's not necessary to have all of that eye candy down below beyond what FTX Global imparts anyway, so it works.  I can, BTW, fly these planes in FTX Aux just fine, and w/ low risk for VAS depletion.

 

So for CS777 & PMDG if and when it arrives:   follow the various suggestions above, but in the end right now you need more CPU.  Even so, pro-level liquid nitrogen cooled Haswell E would still struggle in planes like PMDG T7 out of complex airports in complex scenery.   The software needs an overhaul, that's the main issue.  My hope is that when LM reworks P3D for 64-bit they continue working on the rendering engine using DirectX 12, exploiting more of what Dynamic Parallelism offers, and also rework how multicore/HT systems can be better exploited for components in the simulation amenable to this.  When this happens SLI might offer more for P3D than I believe it current can with respect to complex aircraft.

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Not accurate Noel, proper driver support could shift the balance between CPU/GPU.  

 

Reducing cloud related performance drops could also come from being able to turn off AA on the cloud renders ... probably best done when moving to 64bit as it's significant code change.

 

Going back to square one is not the solution and would only make P3D that much less attractive to flight simmers ... an overhaul is not needed, the quad-tree approach is used in all flight sims.  Continued fine tuning and leveraging modern hardware will produce better ROI.  But more importantly there simply aren't enough resources to do a complete re-write, ESP evolved out of 20 years of coding with 1000's of developers.

 

There will always be a single synchronization thread in any real time environment ... even if you have other aircraft running on separate threads, they must run under a real time world clock otherwise their relative speeds would make no sense in the simulated world.  All been discussed before.

 

Cheers, Rob.

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You're hoping 'proper driver support' changes how complex aircraft will perform in P3D, is this part of what you are saying?  That would be a very pleasant surprise, emphasis on surprise.

 

You've twisted my comment too, which was not 'starting from square one'.  It was: 

 

The software needs an overhaul, that's the main issue [in order to allow complex aircraft to run well].  My hope is that when LM reworks P3D for 64-bit they continue working on the rendering engine using DirectX 12, exploiting more of what Dynamic Parallelism offers, and also rework how multicore/HT systems can be better exploited for components in the simulation amenable to this.  When this happens SLI might offer more for P3D than I believe it current can with respect to complex aircraft.

 

The overhaul I mention is, again, 64-bit & DX12 optimization, and perhaps better multicore utilization beyond texture loading.  You also seem to be stating there is no benefit w/ having for example AI run on separate threads, because of the synchronization need?  Every time I bring this up Rob you retort w/ the same patent dismissal.  You seem to be saying on no uncertain terms, this comment from LR is total nonsense:

 

If you have 20 processors, then you can run TWENTY AI PLANES WITH BASICALLY ZERO FRAME-RATE HIT. Crank the number of planes up to 20 in X-Plane 10 and watch what happens to the frame-rate. Try it now: Set the number of planes to 1 and look at the frame-rate. Then set it to 20 and look again. See the hit? That is because all of those flight models are running on ONE CPU, one after the other, in order. With X-Plane 10, each flight model can run on it’s own CPU, all at the same time… if you have 20 CPU’s, running 20 planes is no slower than running 1.

 

Marketing hype you're saying?  Or some magic not possible w/ ESP?

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Marketing hype you're saying?

 

1.  Are you aware that AI aircraft flight models do run on separate threads in P3D (and FSX SP2)?  

2.  I can't predict how you define "overhaul", but that word to me, represents "starting from square one".

3.  Where did you determine that threading is only related to texture loading - I think you mean "terrain texture loading" not all texture loading?

4.  So what happens with 300 AI planes in XP10?

 

Does LR have access to the P3D source code to make such a comment?  Or is he speculating?  And what product is he specifically referencing, FSX, FS9, FS8, P3D V2.4?

 

The flight models running on a separate thread isn't anything "new" and it doesn't resolve the need to synchronize them so they position correctly in the 3D world.  If it did, then XP10 could only have 3 AI aircraft for a quad core processor ... and as we know, that is NOT the case.

 

Cheers, Rob.

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Nope, not aware of AI models in separate threads, but I am also not aware of most of the intricacies of programming P3D.   My comments to the OP started w/ statements about how complex aircraft performance seems only modestly affected by changing various sliders in P3D V2, and proposed general reasons as to why.  I then conjectured on what avenues might be available to improve the picture, so that complex aircraft might run well in complex scenery, which I maintain now is poorly achievable on current hardware.   The overhaul was defined as 64-bit and optimizing for DX12 essentially.

 

With P3D in its current state, what is the upside for SLI in 'complex aircraft' given an 'optimized driver'?   I TO from default KLAX in the CS777 and show the main thread pegged at 100%, the other 10 handling terrain texture loading etc, but my Titan is lugging along under clocked and lower temperature w/ a reported utilization of say 45%, and a dismal frame rate of let's say 20.  If I now add SLI w/ a 2nd Titan, what happens?   Hard to imagine how a driver revision alone changes this picture.   Dynamic Parallelism looks like a mechanism to help shift the CPU/GPU balance, but it also seems like you need to revise the core engine to accommodate this, so driver revision alone wouldn't cut it, or so it seems.

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Driver "upside" is removing work the CPU is doing that the GPU should be doing and overall efficiency of processing GPU tasks.  Driver updates have provided significant increases in performance with many other nVidia "key" applications in the past ... as much as 70% in some cases.  They've also corrected graphical issues and provided better AA options.  Look at nVidia driver history, they have broken P3D numerous times with WHQL drivers ... frame "buck" stops with nVidia for those using nVidia GPUs.

 

Getting nVidia to no longer ignore P3D I think is a good thing regardless of what it brings to the performance table.

 

I don't think anyone (well actually I'm sure there are a few that would not be interested) interested in a P3D future would disagree with 64bit and DX12 support ... it would be a product that would grow along side existing 32bit product ... but either way, it will be key to get nVidia providing driver support.

 

Cheers, Rob.

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Sounds very helpful, DirectX 12 optimization thru collaboration w/ NVIDIA in 64-bit P3D.  

 

What do you know about how having VAS for current practical purposes unlimited in 64-bit might impact coding strategy?   What is the upside, beyond simply not running out of VAS, in having 64-bit AND lots of physical ram?  Intuitively, it would seem to create more opportunity to cache more and in doing so perhaps smooth out some elements of the sim.  

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1.  Free to allocate

2.  OS level memory fragmentation will be less of a concern

3.  GC can deal with de-allocation "in time" so it less critical for force de-allocation which actually slows overall processing down, believe it or not, maximizing VAS usage is going to be "slower" ... in fact, I think that's what the FSX:SE folks are seeing, better VAS usage but lower FPS (althought I'd like to see Pete's results on FSX vs FSX:SE)

4.  I don't think Cache scenery in RAM is going to be that much of a benefit ... caching textures in VRAM will be a big benefit but 64bit doesn't really come into play here

5.  LM will need to deal with the current tessellation limitation so as to allow higher LOD Radius ... significant change but probably good for a 64bit product

6.  Open the door WIDE for 3rd party content providers ... and I do mean WIDE!

 

Fluidity will most likely come from driver support and not 64bit.

 

My 2 cents.

 

Cheers, Rob.

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caching textures in VRAM will be a big benefit

 

Do you understand what happened between P3D 2.0 and 2.1 or 2.2 that caused reported VRAM utilization to change in such a big way?  I remember reported VRAM utilization would slowly uptick while flying thru complex scenery all the way to close to the max of my Titan's 6Gb.   Since I think it was 2.2 VRAM never goes over maybe 2.2 or so and I never heard the reason why.  Didn't seem to hurt anything performance-wise, but it was interesting to see such a big difference.  I think it had something to do with improving the hit you got w/ vegetation, or something along those lines.  I remember when 2.0 happened I was thinking it was a good thing I had all of that VRAM, now it seems it's not very relevant for me w/ my one 1920x1200 display.

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Do you understand what happened between P3D 2.0 and 2.1 or 2.2 that caused reported VRAM utilization to change in such a big way?  I remember reported VRAM utilization would slowly uptick while flying thru complex scenery all the way to close to the max of my Titan's 6Gb.   Since I think it was 2.2 VRAM never goes over maybe 2.2

 

Not sure what you mean, I've gone above 4GB VRAM usage in v2.4 ... see here:

 

4b3ecc341a1223a229265549680acae7.jpg

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I use the 2D cockpit (iFLY 737).

When running the Ifly 737 in 2D on 1 screen I always have 45+ fps.

And then I have a 3 monitor desktop, so 2 are showing the Windows desktop...

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Not sure what you mean, I've gone above 4GB VRAM usage in v2.4 ... see here:

 

4b3ecc341a1223a229265549680acae7.jpg

Ahh, so maybe this is a function of 2.2 which is what I'm using currently, it is absolutely the case, and very different from prior versions.  Sounds like maybe they discovered this and changed it for what whatever reason in 2.3 or 2.4.

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