Scenery Complexity - Bottleneck In Urban Areas?

[touchdown84 34]

Hi

 

I'm running P3D v2.2 and am very pleased by the performance overall. Normally 30-50 FPS that feel very smooth.

But when I first flew over London a big FPS drop hit me, down to 12-18 FPS and a quite laggy.

 

I tested it standing on London City runway, where standing still I get about 15 FPS.

Tried many settings and most sliders haven't had a really big impact between min/max settings.

On its own, only the "Scenery complexity" slider made a big difference, doubling the FPS to 32 when set from max to min.

The weird part is, the system monitoring shows no real bottleneck:

GPU (GTX 770 SC 2GB): Load at ~50%, low temp, not even running at 100% clock; Mem usage around 1.5-1.7GB

Ram (16GB): Plenty left

CPU (2500k@4.4-4.5GHz): Load at around 30%, one core almost 100%, other three almost nothing

 

So the only thing I could imagine is, that the scenery complexity is single core CPU speed dependent (Affinity Mask 14 or 15, no difference)...

 

When I start flying the FPS stays about the same, even gets better. The GPU load rises and the other CPU cores begin to work (both not to 100% though), so I think all the extra work needed while flying/moving is now processed by resources idle before and the bottleneck is still "Scenery complexity" on its single core.

I don't know why it costs so much CPU resources (that apparently can't be distributed in different threads) for displaying those static objects...

 

Can someone confirm this behaviour?

Are there any solutions/workarounds?

 

Used AddOns:

FS Global 2010

FTX Global & Vector

REX Essential+Overdrive

WoAI

 

Still I'm quite happy, overall performance is much better than in FSX, only other situation where I get even worse FPS is when I get the problems discussed there: http://forum.avsim.net/topic/439800-tips-for-those-suffering-with-cloud-shadow-performance/

 

Cheers,

Jan

[spirit_66 2]

What airplane do you use here?

Spirit

[touchdown84 34]

What airplane do you use here?

Spirit

Stock P3D/FSX planes or Cessnas from Carenado, nothing big or fancy. Tried with a few, results were about the same. 14.5-15.5FPS@max and 27-32FPS@min depending on plane.

[2stepsteve 0]

London and any other large city kills my FPS also, as soon as I leave the area I'm back at 35ish FPS. Admittedly, I do have most quality sliders up to the right, a number are maxed. Level of detail radius maxed, Tessellation factor maxed, Mesh resolution 1m, texture resolution 50cm.

 

If I am flying a 3rd party complex aircraft the hit is much worse.

 

Prepar3D 2.2

FTX Global

FTX Vector

Affinity mask set to utilise all cores.

 

i7 4770K (oc'ed to 4.2Ghz)

AMD 7950 3GB graphics card

8GB RAM

 

Performance in general is fantastic though and I'm not complaining. I need to find a nice balance really, as flying over cities makes the sim unplayable at my current settings.

[Cellinsky 15]

Same here! The only slider I have to be carefull is scenery complexity. One notch more or less at london city airport (stock) makes it a fly or not fly. And its not depend on airplane type. My guess is, that the objects wich are controlled by this slider are not well optimized or even use legacy code. Airport facility  buildings or landmarks that I remember seeing pre fsx. But thats just a guess...

Marcel

[Rollmops 2]

And same here, and the odd thing is that my CPU load is about 50% (about 20-30% for the other 3 cores).

I observed this over EDDF Frankfurt Airport with the Frankfurt Skyline in sight (minus ~9 fps if AI is enabled)

 

I am pretty sure the reason for this are some bad optimized sceneries/(textures?). 

When i compared the textures of the Aerosoft Oslo scenery (which runs pretty smooth on my system) and textures of sceneries that run really bad (as well textures of UT2 AI Aircraft) i noticed that all Oslo-Textures i checked are DXT5 and almost all other textures are DXT1 (with or without alpha...i don´t know).

This is just a suspicion. 

Unfortunately i didn´t have much time to test some conversion to DXT5.  :( And unfortunately i do not have enough knowledge for judging if this makes any sense at all.  :lol:

[DylanM 1,069]

 

 

am pretty sure the reason for this are some bad optimized sceneries/(textures?).

 

There definitely seems to be more of a hit at some complex areas than others (e.g. KSEA is noticeably heavier on the system than CYVR) hinting at optimization issues for custom ORBX autogen.