Performance hit after hard braking on runways

[bamboofats 0]

Hi all, I noticed that after landing an fps heavy aircraft like PMDG 747, i often experience some fps drop while taxiing away. I then did some testing and noticed this on RTOs,. I first thought it was due to the increased brake temps, as the fps drop was somewhat related to the brake temp. After much testing I narrowed the problem down. With another aircraft like the default 737, I did hard braking on runways and when viewing the part of the runway which braking was done there would be a performance hit. Has this bug been documented before, or is it just my rig?Heres how to reproduce it, (at least for me),load an aircraft, ( i tested with PMDG 747 and default 737) onto a runway.Notice the frame rate (using the frame rate viewer), it should be decentto isolate it, load on a clean runway, with no traffic, or weather(clear), paved long runway.accelerate, at about enough speed, eg 140knots or so, slam on the brakes. come to a stopNow pan the camera around in external view, when the camera passes the portion which you did hard braking, fps will dropIts as if the wheels left some nasty invisible tire marks that eats fpsTo enhance this phenomenon, I used unlimited framerates, and applied thrust while full braking to maximise the braking roll, all the way to almost the end. .Thus with the runway full of the 'invisible tire dust', or 'large amounts of braking mileage' given to it by the aircraft, the fps drop was massive.For the default 737, it went from 150fps to 40 fps. (prior to and after braking)For the pmdg, it went from 60 to 12fpsAfter a few minutes, the fps then goes back to the high amount, all the magic dust disappears. If you limit your fps to say, 30 or 40, using the 737 you wont notice anything, but using an fps heavy craft, the drop is quite noticeable. Your taxing off the runway with jerky fps for no reason.Is anyone able to reproduce this? If so, is there a fix for it? I am using ATI 5870. ThanksLee

[Benjamin J 751]

Can't this simply be related to buildings that have to be loaded by the sim? When you land and turn off the runway, chances are you'll once again view all the terminals and such - meaning FSX will have some drawing to do and FPS might drop while it does that. Could you set scenery complexity to the lowest possible and re-run your tests?

[Kosta 122]

Wow, I believe I can too reproduce this!Just tried with with PMDG 747, and voila... when I brake down from 120 to 0, and then look back from external, my FPS which are unlimited for the sake of the test, drop from around 50 to below 30fps - I tried slewing around, and each time when looking AWAY from the braking part of the runway, FPS are high. Look there, voila - a drop.I think you are onto something here.EDIT:HARDCORE!!! Just tried a non-addon airport which gives me 105fps when in external of PMDG 747. Same procedure - up to 120, brake down - look back - down to 23fps! LOL!!!And so that we don't pin this on PMDG 747 - default Learjet - 156 vs. 54 after braking.There is something seriously wrong here.

[bojote 20]

Is anyone able to reproduce this? If so, is there a fix for it? I am using ATI 5870. ThanksLee

Do you have REX installed?

[Kosta 122]

Do you have REX installed?

I do...I uninstalled it, tried, at first try, it seemed better. But then again, 2nd try - another airport, another aircraft, still same old drop.I think this is a real FSX bug.Only way to be sure - vanilla FSX.

[AlphaInfinity 13]

Did you restore the origonal FSX textures from backup via the REX UI before you uninstalled REX?

[bojote 20]

I do...I uninstalled it, tried, at first try, it seemed better. But then again, 2nd try - another airport, another aircraft, still same old drop.I think this is a real FSX bug.Only way to be sure - vanilla FSX.

Hi Word Not Allowed, look in your ROOT/FSX directory. GO inside the texture folder and look for this files:runway_detail.bmprunway_detail02.bmptaxiway_detail.bmptaxiway_detail02.bmptell me the size of the above files, and while you are at it, get a vanilla FSX SP2/Acceleration install and use the above SP2/Accel files instead of the ones you have installed and try again.

[bamboofats 0]

Hmm, this doesnt seem to be a texture problem. I tested with the REX textures and using default ones and both exhibit the same slowdown. I am using FSX Sp2 non acceleration btw. And yes, My airports are totally clear, no terminals, no autogen, no traffic. Just the rwy and the plane. I even tried with textures down to minimum, details off, shadows turned off, texture filtering switched off, advanced animations turned off. All the settings there. Though they help with the base fps, eg (150fps to 20fps drop) becomes (200+fps to a 40fps drop), the slowdown still exists. All kinds of brake action does this, from high speed braking RTOs, landing braking, applying full thrust with parking brakes on and letting the plane slide forward a few metres, all give the problem. However, reverse thrust/spoilers slowdowns without brake application will not trigger it. If this is really a bug it is a very strange one. Slowdowns after braking when there are no visual changes, tire marks, and it returns back to normal after about 3-5 minutes? This is so weird. Its like there is some messup with tire physics, contact physics or the game is trying to calculate something and somehow got out of control. My guess its a load on the cpu, not the gpu. Does this bug happen to you all? Give it a try haha. Lee

[Kosta 122]

Hi Word Not Allowed, look in your ROOT/FSX directory. GO inside the texture folder and look for this files:runway_detail.bmprunway_detail02.bmptaxiway_detail.bmptaxiway_detail02.bmptell me the size of the above files, and while you are at it, get a vanilla FSX SP2/Acceleration install and use the above SP2/Accel files instead of the ones you have installed and try again.

1,367 all four.

[Kosta 122]

I can safely report now it's NOT REX fault.I installed FSX+SP2 vanilla with a following result: view back from the front of the aircraft, spot, 96fps (it's another cfg so that's why lower initial fps), after hard braking (RTO for instance), 34fps.Now I kinda know why I always had such terrible performance on landings. This explains it.And to even try something really weird: I take off from such a runway, where I did brake, and then fly around the airport, when I have it in my sights, FPS drop to 50, when not, 150+...After 5 minutes, everything is peachy.A reason more for me to fly FS9, as I am still doing...

[bamboofats 0]

Yes, i have tested it again on my friend's computer, which isnt powerful so settings are minimal. Recent install, Vanilla FSX, SP1, no addons at all, all graphic settings switched off (you can imagine how horrible it looks), but a decent fps of about 50 achievable most of the time. Same frame hit with the braking strip, down to 20 or so. standard default A320 or B737I used to wonder how come the PMDG 747 was giving strange fps jerkies after landing. It turns out that this happens to all aircraft, but with the PMDG giving a higher system load, this fps drop effect becomes much more noticeable. Strange stuff. Its like Fsx is trying to calculate something, like runway surface friction temperature increase?!? (-___-) , when nothing of impact is apparently simulated.Just wondering does anyone not have this problem? Maybe theres a reason like some incompatible hardware, or settings??? If its an FSX bug, is there a workabout for it? (i would seriously doubt anyone can do anything at this time)Lee

[Kosta 122]

Yes, i have tested it again on my friend's computer, which isnt powerful so settings are minimal. Recent install, Vanilla FSX, SP1, no addons at all, all graphic settings switched off (you can imagine how horrible it looks), but a decent fps of about 50 achievable most of the time. Same frame hit with the braking strip, down to 20 or so. standard default A320 or B737I used to wonder how come the PMDG 747 was giving strange fps jerkies after landing. It turns out that this happens to all aircraft, but with the PMDG giving a higher system load, this fps drop effect becomes much more noticeable. Strange stuff. Its like Fsx is trying to calculate something, like runway surface friction temperature increase?!? (-___-) , when nothing of impact is apparently simulated.Just wondering does anyone not have this problem? Maybe theres a reason like some incompatible hardware, or settings??? If its an FSX bug, is there a workabout for it? (i would seriously doubt anyone can do anything at this time)Lee

I highly doubt that there's anyone without this problem. Not many noticed it due to the FPS limiter set to 25 or 30 fps mostly. People always reported slower FPS on landings, and I guess we all lived with it. I guess people simply don't care... I wasn't able to find out what caused it. Now we know. I thank you.

[bamboofats 0]

ok, Well at least knowing the problem solves half of it?? Haha, at least is doesn't affect performance while in the air, and I don't spend lots of time on the ground anyway. Probably have to live with this, there's no way Microsoft can/will fix it now. Anyway thanks for your attention. Lee

[RelaxX 11]

And to even try something really weird: I take off from such a runway, where I did brake, and then fly around the airport, when I have it in my sights, FPS drop to 50, when not, 150+...After 5 minutes, everything is peachy.

It's pretty irrelevant if the FPS drop from 150 to 50 after hard braking. All you need is a smooth operation at ~ 30 FPS with very good image equality.This can easily be achieved with an Intel processor having a core speed of ~ 4 GHz. You can find the details in my FSX guide.

[bamboofats 0]

That was part of the testing, to show that the problem exists there. Its not that irrelevant if someone's rig is running close to the edge with all the details, like 30 or 40fps, and being limited to 30fps. And with this effect coming into play, his fps drops to 15 or 12 after hard braking. That person would have an extra load on his rig in addition to all his enhanced graphics, for no reason. Now his FPS limiter or all his tweaks wont help him in this case.If his real fps(without limits) is already higher, like 60 or so, he would have a buffer zone, and the fps drop wont be noticed. But if the real fps is already close to the limit, this effect is going to make those few moments of taxing quite uncomfortable. Of course i dont expect his problem to be solved. Just have to work around it. Either you have a good enough computer/ settings such that there's extra fps/performance to spare to prevent the fps from dropping below the limiter, do minimal braking, avoid looking at the braked area, or just live with the slowdown for a few minutes.