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Rafal

AI traffic performance - myths and reality

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Hello everyone,

 

I probably could write a novel on this. But since nobody would read it, let me try to be as brief as possible.

 

In my FS9 world I enjoyed airports full of various AI traffic for years. When, in 2013, I switched to FSX, it stopped being enjoyable.

Using AI traffic, payware airports and airliners (yes, I am a big tube pilot) plus real weather, I had to compromise sliders, like most of you.

Even then the performance was rather bad.

 

One year ago I bought iFly 744 (I love 747) and decided to celebrate it with a 744 world tour, starting in the US. Performance was terrible and after landing at Flightbeam Denver with FPS in just single digits, I thought that was enough. I removed my thoroughly made AI traffic and since that time I started flying empty airports. Without iFly, as I hangared it due to its low performance, usually flying NGX (plus a bit of 777 and Majestic dash). It lasted a year until recently IFly released the SP1a patch addressing performance. It did improve the performance for me, so I decided to celebrate the 'No Traffic Year' with returning to AI traffic. So for the last week or more I was again preparing my AI traffic, making sure it is up to date (latest flightplans and liveries - mostly of FAIB, TFS, AIA and UTT), FSX compiled (thank you, AIFPC!) and free of errors (thank you, ACA2013!).

 

Earlier today I made an iFly 744 flight between EDDF (German Airports Team) and EGLL (Sim-Wings). I know, they are huge airports, but that was deliberate. I thought if I can do it, I can do any other flight. To my disappointment (not that I expected good performance, but still), I was getting 11-14 FPS on average at EDDF, I got OOM warnings on finals to EGLL and saw single digits leaving the EGLL runway 27R (by the way I didn't make it to the terminal, as my FSX OOM-ed).

 

So using the fact I have a free Saturday, I decided to perform some tests, and would like to share the most important results with you.

 

I have read many times that leaving the AI traffic slider at 100% is asking fro trouble. Various folks recommend lower numbers, some 10%, others 25%, still others 50%.

But, after checking these numbers today, I came to a conclusion... there is no difference between the way the AI traffic slider influences the performance!

I checked 10%, 25%, 50% and 100% AI traffic at my Mega Airport Frankfurt to see no performance change. See the screenshots presenting three of these situations:

 

traffic_25_S_zpsk9osd31g.jpg

 

traffic_50_S_zpsqgmcuy5n.jpg

 

traffic_100_S_zps9xup7ryl.jpg

 

As you can see, the number of AI aircraft remains the same, regardless of the slider's settings.

Performance too, by the way. I saw no FPS difference until I switched the traffic off completely.

 

As we know, performance is not only FPS, but also VAS. So I decided to check its behaviour depending on using AI traffic.

Again, no difference with different slider's settings! I had around 3.2 GB remaining with 25%-100% of traffic at EDDF in iFly 744 VC.

Without traffic, it went up a bit, to 2.9 GB left.

 

Now, some folks do not mind seeing empty airports in FS. For a year I tried to convince myself I could belong to that group too. But I think I can't. It takes away a lot of the immersion I feel simming. I thought reducing the traffic slider will be a partial solution but, as you can see, it doesn't seem to be. Of course there is VATSIM but, even though I used to be an active on-line pilot years ago, currently (for a few reasons I am not mentioning here) I rather fly off-line. And when I do, those empty airports look like after a nuclear war or a global airline bankruptcy.

 

I wonder what your experiences with AI traffic and performance are, especially concerning FPS. I will be very grateful to read some replies.

I also wonder if those of you who tried to check, can confirm my observations about no impact of the traffic slider.

 

I have autogen set at normal or dense, water low 2.x, and clouds textures to lowest possible.

I don't use (U)HD textures and I have TEXTURE_MAX_LOAD=1024 set at FSX.cfg. Of course HIGHMEMFIX=1 is there too.

 

I am on i5 2500K 3.3 GHz @ 4.0 with 8 GB DDR3 RAM and GTX 560Ti 1 MB.

I use FSX (non-SE) on 64-bit Windows 7 HP.

 

I consider buying a new PC next year (this one in 4 years old now) but I am not sure on how much it would improve my AI traffic experience.

 

In the end I would like to make two things clear:

1. I am not addicted to watching FPS numbers, I know it is not good. It usually is off.

I turn it on only for tests when I see something is deffinitely wrong and the minimum required (for my eyes) fluidity is broken.

2. For me there is no way back to FS9, and as for P3Dv3, I am considering it next year.

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Timely post Rafal. Like you, flying seems sterile to me without traffic. I just did some AI performance testing last week. I use MyTrafficX and wanted to compare ver 5.4b with the new ver 6.0 and 6.0a-beta4. It is a bit of a mish-mash because I have 5.4b installed in FSX dx9 and ver6 installed in P3D. The format of the data below is "airline ai traffic density/total number of ai aircraft/number of ai aircraft at airport/FPS. For the tests I had my scenery settings maxed out in both sims, no shadows in either because it brings fsx to its knees, all other traffic at zero, clear skis. The aircraft I used was the default beechcraft baron as it is in both sims and other people could perform comparison tests. I performed the test with my aircraft on runway 35R at KSEA and also on runway 31L at KFJK. I was in the virtual cockpit, zoom 0.8 looking straight ahead and both airports are default airports. I used the freeware software AI Traffic optimizer available on the Avsim forums to count the AI traffic. I also set the date for 11/30/2015 at noon local time. The day/time effects the AI traffic schedules and number of aircraft. Now the data:

Seattle KSEA 35R

FSX ver5.4b          P3Dv2.5 MyTrafficXv6.0       P3Dv3 MyTrafficXv6.0           P3Dv3 MyTrafficXv6.0aBeta4         

0/0/0/60                 0/0/0/48                               0/0/0/50                                 0/0/0/50

5/20/4/60               5/28/16/41

10/42/16/60           10/40/20/40

15/70/31/55           15/55/25/39

20/97/40/52           20/74/26/38                         20/76/25/44                           20/109/77/30

25/114/46/50         25/86/30/37

30/138/48/49         30/106/32/36

35/155/55/47         35/117/35/35

40/167/57/46         40/135/37/34                       40/136/36/40                         40/193/94/29
 

 

New York KJFK 31L

FSX ver5.4b          P3Dv2.5 MyTrafficXv6.0       P3Dv3 MyTrafficXv6.0           P3Dv3 MyTrafficXv6.0aBeta4

0/0/0/60                 0/0/0/60                               0/0/0/60                                0/0/0/56

5/27/9/60               5/79/37/43

10/113/41/50         10/114/52/40

15/193/63/41         15/158/73/35

20/264/83/33         20/181/81/34                       20/185/80/34                        20/269/105/31

25/308/99/32         25/213/87/31

30/334/108/31       30/228/92/31

35/354/113/31       35/252/94/30

40/373/123/28       40/273/97/30                       40/267/94/30                        40/455/181/21

This is by no means any kind of scientific test as I am comparing three different traffic versions in two different sims. I got tired as I got to P3D ver3 and so only tested the 20 and 40% AI traffic levels. I intended to put MyTrafficX v6 into FSX and test again  but didn't have time. The data does give you an idea of the effect of the traffic slider in each case. My system is a 3770k at 4.5ghz, 8gb of 2400 Ram, and a 780GTX. As you can see my traffic is definitely reduced by lowering the traffic slider. However it doesn't take a very high percentage to bring down the FPS, especially with the latest beta version for MyTrafficX. With a complex aircraft like a PMDG I used to fly at 15-20% AI traffic. with the latest beta from MyTrafficX I've had to reduce that to 10-15%. As you can see that still gives a fair amount of traffic.

If your sim is not removing traffic as you reduce the AI traffic slider you have something else happening. Did you ever have Ultimate Traffic installed on your machine? I never had it but understand that the traffic levels in that are controlled outside of the sim. It sounds like there might be some traffic files that are not turning off.

AI has a big impact on performance but I don't know if the impact is more on the CPU or GPU. You have a fair CPU but your GPU is definitely weak, especially for P3D. One other thing, Auto traffic also has a large impact on FPS if you are using that also. I only use auto traffic with my GA flights.

I would suggest that you download the the AI optimizer from the link on the thread here at Avsim. This would allow you to see how much traffic is loaded at each setting. Also there is a long ongoing pinned thread called FSMARK11 in the hardware forum that has the results from various participants tests using a saved test flight. You could look for a test done on a system similar to yours or download and run the test flight yourself.

Hope this has given you some insight,

Ted
 

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What influences performance is the number of aircraft within the user's reality bubble. In the case presented in the first post, it's very possible that all those percentages yielded more or less the same number of AI aircraft in the bubble. This can happen if one is either near or at a large international airport.

 

The second post illustrates the interplay between the somewhat toothless percentage controls in the sims' UI and the number  of AI aircraft within the bubble. The TO is the best solution to the flaw in both FSX's and P3d's control of AI traffic densities.

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 Keep in mind Raf with your traffic percentages, AIFP doesn't randomize the traffic % unless you specifically tell it to. AIG's plans are most often all left at 1% unless you change the percentage. The traffic % slider works very well but your traffic also needs to be configured for it to work.

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Keep in mind Raf with your traffic percentages, AIFP doesn't randomize the traffic % unless you specifically tell it to. AIG's plans are most often all left at 1% unless you change the percentage. The traffic % slider works very well but your traffic also needs to be configured for it to work.

I was just about to say the same thing.

 

A lot of people who use WOAI experience the same thing due to the majority of the flight plans being set to 1% and see the same thing as what Rafal when they dial the sliders back.

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Gentlemen,

 

Thank you so much for your valuable replies! There is so much precious information for me to make use of.

 

While I consider myself to be fluent in creating AI traffic (have been successfully doing it for a decade or so), at the same time I happen to have problems with understadning how some things really work in the MFS environment. You insights give me a lot of food for thought.

 

I have to analyse what you wrote in detail, however let me now reply to a few sentences.

 

Did you ever have Ultimate Traffic installed on your machine?

 

No, Ted. To be honest I have never used any traffic addon software. I have always compiled my own traffic using available models, repaints and flightplans.

 

You have a fair CPU but your GPU is definitely weak, especially for P3D

 

While I'm still on FSX, not P3D, I am aware my rig is not new (over 4 years old now), and the GPU is indeed not the latest generation to say the least.

Of course I could change the GPU into a better one, but I think it will be better to buy a whole new PC, which may (hopefully) happen sometime in 2016.

Or do you think changing the GPU itself, before buying the PC some months later, would make a visible difference in performance (especially concerning traffic)?

 

Auto traffic also has a large impact on FPS if you are using that also. I only use auto traffic with my GA flights.

 

Ted, by 'Auto' do you mean the ground (road) traffic? If so, then unfortunately you are so right about the price you pay for using it. But I don't use it.

Seeing screenshots featuring cars on the roads was one of the reasons for me to dream about switching from FS9 into FSX.

Once I did it though, I quickly stopped using it, seeing how it kills my FSX performance. It's a pitty. Now I laso turn it back only occassionally, when I take a GA plane for a ride.

 

I would suggest that you download the the AI optimizer from the link on the thread here at Avsim.

 

That's great idea, Ted. I will do so. I have already tried it, but I got discouraged as it didn't seem to work for me.

I will now give it a second try as if it does what it promised, it could help with flying into large airports.

 

Now, I see lower teens down to single FPS digits only at the largest airports, like EGLL or EDDF. When tested yesterday at small and medium airports (e.g. EPKK, LHBP, USSS, EDDH, EGCC, LSGG or LGAV), where the amount of traffic aircraft is clearly lower, I got quite acceptable results, about 20-25 FPS in my VC, which for me is enough to enjoy flying. So the best idea for now seems to be just avoiding large hubs and limiting my flying to small and medium size airports. Could be done. I'll just have to hangar my 747 again, as I see it destined for large aerodromes. :smile:

 

 AIFP doesn't randomize the traffic % unless you specifically tell it to. AIG's plans are most often all left at 1% unless you change the percentage.

 

Dave, that is interesting. I didn't think about it at all. Now, how to change it, that is the question!

 

 

Now, Jay, I would also like to reply to you, but since the AVSIM forum software prevents me from using more quotes, let me do it like this:

 

'This can happen if one is either near or at a large international airport.'

Right, Jay, the problem is I experience the slideshow only at large airports! :P

 

'The TO is the best solution to the flaw in both FSX's and P3d's control of AI traffic densities.'

What does the 'TO' acronym mean in you post? I am asking as I feel excited about a possible great tip standing behind it.

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Hi Rafal,

 

it is very difficult to say, because maybe my almost enthusiastic hardware would behave in a different way when you use it. I use AIFP and UT2 and I am happy with it. Well, at my AS-EDDF, not all stands are occupied, because it is not realistic I think. But there are enough, maybe 30. Additional 6 moving Ai are ok too, when making a t/o or a landing, maybe more, it depends on so many things.

If you are thinking about new hardware, don´t make any rotten compromise. If you can afford it. Make the full pull :Party:  and you probably won´t regret it.

The manual of AIFP explains the % sliders, have a look there and find your balance. :wink:

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A few other things to bare in mind.

 

1. The "bubble" in a 10 mile radius for aircraft traffic.

 

2.. There are three separate things with AI aircraft which affect performance, the number of AI aircraft and the size of the textures. Payware programs also include large AI Aircraft graphics, while WOAI and MOST other freeware libraries have great looking, low memory aircraft. The third thing is the taxi path and flight plans which AI aircraft use.  The greater the number of junctions (vectors) the more processing is required.

 

3. The processor thread for AI Aircraft is deliberately different than the thread for AutoGen. There is a problem with FSX in which the same data is processed on different threads, essentially processing data twice thus increasing processing overhead (bandwidth). This was initially seen with graphics processing, and Dovetail Games discovered (or rather confirmed) this and did a good job in reducing the problem (good reason to update to the stream version). LM did the same thing with P3D.

 

Believe it or not, flying on VATSIM reduces the processor impact on AI traffic because some of the processing done with AI traffic does not have to be performed. You'll still get some frame rate drop at very large VATSIM events, however I've been at airports with upwards of 150 aircraft and still had frame rates at 15% with my older first generation i7-960 rig.

 

I'm not a fan of overclocking where 2nd generation i7 processors are concerned, and this case brings up yet another good reason to avoid pursuing the fastest processing speed via overclocking. The more one over-clocks, the greater the timing issues (I'm not talking about bottlenecks per se) between the CPU and GPU can become.  The more processing required of both the CPU and GPU, the greater the impact of timing between them.  Moderate overclocking (or my preference of maximizing the Turbo mode seems to be fine. Of course EACH COMPUTER RIG IS DIFFERENT, so you'll have to determine this for yourself.

 

Finally, the advice to turn Hyper Threading off has been proven time and again, so this too can help.

 

I sincerely hope you find this useful.

 

Best wishes to all for enjoyable flights!

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at my AS-EDDF, not all stands are occupied, because it is not realistic I think.

 

You are certainly right! Once I find the way to make it happen at my EDDF (with more than 100 AI aircraft!), it will make the difference.

For now I can always disable my traffic_Lufthansa.bgl - that will change EDDF for sure (same for BA and Virgin at EGLL). :wink:

 

If you are thinking about new hardware, don´t make any rotten compromise. If you can afford it. Make the full pull

 

That is planned. I will have to discuss it a few more times with my wife who probably believes my 4-year-old PC is still OK (actually it is, but you know...).

 

The manual of AIFP explains the % sliders, have a look there and find your balance.

 

Yes, RTFM is going to be the right thing to do tonight.

 

(good reason to update to the stream version). LM did the same thing with P3D.

 

I don't think I will be moving to Steam, but P3Dv3, as I mentioned above, is planned for next year (rather with the new PC).

The advantage of waiting, by the way, is gaining time for some not yet compatible products to become compatible. :smile:

 

You'll still get some frame rate drop at very large VATSIM events

 

I once took part in Frankfurt Overload and that was my all times worst VATSIM experience. Guess why!

 

Once again big thanks to everyone who cared to take part in this discussion.

I would think I know everything I need after over two decades of simming.

But it is so far from the truth. We learn all our lives, once we want of course.

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Hi Rafal

I use FSX-SE and haven't had much problem with high numbers of AI except at some of the Mega airports like EGLL etc. and then I have to adjust the sliders to get that right balance. As one of the other posters said, I think Steam Edition handles things better than the boxed version.

 

Just a couple of other suggestions:

1. I have tried to optimize my AI aircraft by using FSX models whenever they are available. I also use DxtFixer to make sure the textures have alpha channels, are DXT3 etc.

2. Checking all your AI files to make sure there are no missing aircraft can make a big difference. If there's an aircraft missing then the program keeps trying to load it and that can cause serious loss of performance. I have found that just a few traffic files with a missing aircraft or two can seriously degrade performance. It's a bit time consuming, but using AIFP makes the process pretty fast and easy

 

Like you, I have found transitioning from FS9 to FSX-SE a mixed blessing when it comes to AI. The positives outweigh the negatives but there were and still are some things FS9 does better and AI is definitely one of them

Cheers mate

Ian

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The positives outweigh the negatives but there were and still are some things FS9 does better and AI is definitely one of them

 

You bet, Ian! Let's hope P3D will shape into an almost perfect solution in the nearest future (I've read it's on its way there). :smile:

I mean being able to effectively utilize today's hardware, which FSX (in my view) is not really capable of. FPS, VAS (!), lighting, animations, etc.

 

It's a bit time consuming, but using AIFP makes the process pretty fast and easy

 

I recommend ACA2013 for that purpose. Saves all the headaches.

 

I have tried to optimize my AI aircraft by using FSX models whenever they are available. I also use DxtFixer to make sure the textures have alpha channels, are DXT3 etc.

 

I also use FSX models everywhere it's possible. As for the textures, in 90% (sometimes there is no FSX repaint) I use DDS, which are FSX native. Mipped if possible.

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Rafal, another solution that you could do to still have the ambiance at the airport but not get killed on approach to huge hubs is to zap all traffic on approach and then turn it back on once you've vacated the runway.

 

Since your using .bgl based traffic files you'll get a quick scenery reload when you turn the traffic back on, but it shouldn't take too long. If you have the registered version of FSUIPC you can use a feature of it to assign a hot key to shut off traffic and then turn it back on without having to access the menu to do so.

 

The other option would be to buy UT2 which doesn't use .bgl traffic files and already has those functions included to either turn traffic off or reduce the percentage on the fly all by using hotkeys. Since you take pride in keeping the flight plans up to date you can use the UT2 Powerpack to import your schedules and planes/paints, etc.

 

Something to consider.

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If you have the registered version of FSUIPC you can use a feature of it to assign a hot key to shut off traffic and then turn it back on without having to access the menu to do so.

 

A great idea, cmpbellsjc! Till now I thought the FSUIPC Traffic Zapper works just for single AI aircraft and I used it to clear occupied airport stands.

But now I see you can turn off the whole traffic! I do have the registered FSUIPC, so will test it as soon as possible. You learn something every day. :smile:

 

The other option would be to buy UT2 which doesn't use .bgl traffic files and already has those functions included to either turn traffic off or reduce the percentage on the fly all by using hotkeys

 

That also seems to be a great idea. However as I love creating my own traffic and rather spend every euro on addon aircraft and airports, I will have to think twice.

But in case I go for it one day, thanks a lot for telling me it offers such possibilities.

 

Once again, thanks a lot!

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