+18 votes
asked by (30 points)
edited by

Here is my system specs.

  • i7 5960x (3-3.5 GHz, 8 cores / 16 threads)
  • 128 GB RAM
  • GeForce GTX 1080 8 GB
  • Windows 10 Pro

With these specs I assumed I would get decent frame rates, but I'm getting between 20-30 fps with the following settings:

 

I have even pushed it all to the max - there's literally no change in frame rate. The only way I've been able to get a better frame rate is if I turn everything to the minimum - then I can get up to 40 fps. Adjusting texture qualty does nothing to performance, neither up or down. Adjusting antialaising have no impact. Number of world objects obviously have some impact, but not more than 1-3 fps.

 

And here's the interesting thing: the CPU is almost idle.. It's only running at 25-30% load, while the GPU is around 30-40% load.

It does not matter if it's a Cessna 172 or a Boeing 737. I thought it might've been due to the AI planes, so I removed all of them too. Did not change the CPU or GPU load, or increase performance.

So what am I missing? Why can't I get better and more fluid performance?

 

 

For some reason the images I upload are scaled down a lot... Here they are attached.

imageDownload file

imageDownload file

 

commented by (110 points)
Much the same here -

i7-6850K (3.6-4.0 GHz, 6 cores, 12 threads)

32 Gb DDR4 ram

nVidia GTX 1080 8Gb ram (to 4k monitor)

Asus Rampage 10 motherboard, oc'd

Windows 10 Pro

All CPU cores running but total CPU utilization ~ 27%

GPU load shown as ~ 40%

With much the same settings fps ~ 24 at Bradley Intl.

This same computer will run CPU/GPU intensive games (e.g. Witcher 3) at 60 fps (max for the monitor)

Thanks...
commented by (30 points)
A friend of mine purchased X-Plane 11, and wanted some help on how to start up, so I made the plunge and purchased it too to help him, and some day, hopefully fly together.

So what have I discovered? The KSEA area is a terrible performance drain, and in my opinion, a terrible location for a "demo" area, because as you can imagine from my first post here, I took it as the defacto performance I would expect from the simulator as a whole.

 

When I fly in the area I usually fly, which is Norway, even with third party scenery, I get far better and stable frame rates. I hover between 25-40 fps depending.

Yes, surprisingly, it's the same frame rate, more or less, as I wrote about in the opening post, but somehow it feels way more fluid and acceptable now than before.

Laminar, I don't know what you can do, but please take note of this.
commented by (19 points)
I have noticed,in my case, that X Plane software does not utilize hyperthread well at all. Please, in your motherboard bios, disable or turn OFF hyper-threading.  (Caution: You may have to re-register some of your ad dons) It seems making adjustments to your motherboard causes some registrations not to recognize your motherboard thus view the change as a different machine causing the request for a registration key.

Remember, X Plane and hyper-threading oil and water, they do not mix. From my  reading, X Plane programmers must first program the software to take advantage of the multiple cores in the CPU. Until they do, X Plane 10 and 11 are single thread operating software.

Rthomas18
commented by (10 points)
The developers said people should be happy with 25+ frame rate. One thing I have also noticed is that reflection detail kills frame rate.

6 Answers

+2 votes
answered by (28 points)

Back in April 2007, Ben Supnik provided some very useful information, which is still valid:

"Times have changed and neither the sorting nor the alpha-drawing is even remotely expensive on a modern machine. So I was surprised to see the CPU not being used. After some investigation, it turns out that while the CPU and GPU have gotten a lot faster over time, the communciations channel between them has not. The result is that they both do their jobs really quickly, and as a result clog up the communications channel…the CPU simply can’t talk to the GPU fast enough to get the clouds out. "
Source: http://developer.x-plane.com/2007/04/cpu-or-gpu/

Why is this still valid? This is exactly the reason why AMD developed Mantle (now part of Vulkan API), Microsoft developed DirectX 12 and Apple developed Metal. These Application Programming Interfaces (APIs) were developed to overcome the limitation of single threaded transmission of commands from the CPU to the GPU and take full advantage of current and future CPUs' multi-core and multi-threaded capabilities.

Furthermore, since this was a known problem in X-Plane ten years ago and X-Plane 11 still uses the OpenGL API, there is no reason to believe that X-Plane 11 does not suffer from the same problem as its predecessors. Even worse, as the number of objects in X-Plane 11 has increased, the bottleneck of a single threaded loop is now exhibited at its glory!

In my opinion, Laminar Research (LR) should focus their attention into two core parts of its product:

1) Develop an efficient 3D engine that takes advantage of cross-platform Vulkan API, and
2) Develop a UI engine that allows for use of Virtual Reality (VR) equipment, to greatly enhance immersion.

Excuses in the form of "this is BETA and shall be further optimised" are distracting. Yes, the 3D engine can be further optimised but only to the extent OpenGL allows, i.e limited by single-thread performance. OpenGL was not developed with mass-scale multithreading in mind, it's no longer good enough.

Unless X-Plane's 3D engine is migrated or rewritten for Vulkan, the bottleneck will be there. Yes, it's not a small undertaking, but it is essential if the game is meant to be visually compelling.

Honestly,
Nikos

commented by (60 points)
You learn something every day, haha.

A lot of people come for the visuals, so xplane is probably being careful.
+1 vote
answered by (21 points)

I have absolutely the same problem with my PC Configuration. Low FPS on High Settings, between 9-11 FPS! This is to low, compared to other Systems with a smaler CPU and GPU, but with 30FPS on the same Settings. 

System Specs:

  • Intel 3970X @ 5GHz all Cores (12)
  • Corsair 16GB RAM
  • Nvidia GTX Titan Black OC
  • Windows 10
It looks like the multicore processing does not work properly. The cores hold themselves up and the GPU is overloaded with too much of the same information, or must wait too long, depending on the utilization.
commented by (21 points)

I could identify a part of my problem when the mutlimonitor is disabled, I have less FPS than with Multimonitor Settings. However, the FPS are playable, comparable to the system still bad

Link: https://youtu.be/ldn5JacNTW0

0 votes
answered by (866 points)
@olahaldor

Wow, that is a lot of RAM! Thanks for the detailed post, by the way.

And @Towerkeeper

From someone who loves PCs, you both have awesome computers. :)

Anyway, can you both please upload the log.txt file? I also want to point out that since X-Plane 11 is only in Beta, strange things are bound to occur. It is likely some sort of bug, but hopefully the log.txt will point us in the right direction.
commented by (30 points)

I take my job to the home office from time to time, and I really need that RAM. ZBrush and World Machine can be very demanding. :)

Here's the log attached.

 

commented by (110 points)

Not sure if this will help, attached are three logs:

: log_min  - all sliders set to minimum

: log_int    - all sliders (except alias) set to max

: log_max - all sliders (inc. alias) set to max

Log Summary
log #FRCPUGPU
min40-5054%37%
int17-2423%31%
max7-973%98%

Seems that CPU / GPU utilization can run/be somewhat counter-intuitive.

 

imageDownload file

imageDownload file

imageDownload file

commented by (866 points)
@olahaldor

Do you work for an animation company?
commented by (30 points)
Yes, among other things.
0 votes
answered by (19.3k points)

Since X-Plane 11 is still in the very first set of beta testing, we will need information like this to start turning the performance. Please submit a bug report (if you haven't already) with all this information so we can keep track of the systems that have performance issues. 

commented by (30 points)
Okay. It's Done.
commented by (11 points)
edited by
I have probably similar problem here (even though far from that powerful machine above :) ) .

I am running x-plane 11 beta on  
 

Windows 7

AMD 6300 overclocked to 5GH ,

16GB RAM

Nvidia  970

I have framerate average 12 by default settings.

When I put all settings to minimum I have same framerate - nothing changes.

It is basically a slideshow.

Still CPU is utilized to 90% - all cores. Even when simulator is paused, or I am in the settings menu and nothing moves - CPU is same up.
commented by (11 points)

Just adding screenshots

framerate - lowest settings

 

0 votes
answered by (18 points)

Hello guys,

I have smaller than expected amount of fps on my PC too. I have 15 to 20 fps, not on such powerful machine as the first poster, but still, im not used to 20 fps :-)

  • i7 6700
  • 16 GB RAM
  • GeForce GTX 1070
  • Windows 10

With my PC, the GPU also doesn´t reach the 100% od load, or memory use (although I have warning in event viewer: "The NVIDIA OpenGL driver has encountered an out of memory error" (http://questions.x-plane.com/4997/x-plane-11-causing-opengl-out-of-memory-error). Maype you could check the event viewer too, if warning is there.

Here is screen when X-Plane 11 is running and I´m attaching the log too.

 

 

commented by (866 points)
Once again, X-Plane early Beta stages. Please report this as a bug here: http://dev.x-plane.com/support/bugreport.html

This will help the developers tune X-Plane as necessary. Thank you.
commented by (15 points)
I have the same problem, and had the same problem with XP10. I have an AMD Fury 4gb VRAM and a I5 6600K 4.5GHZ and 16gb of 3200mhz ram on a Samsung 950 pro 2500 mbps and I get 20-30 FPS! This is laughable!

In P3D with add ons of all types at 4k texture res and 4k screen res and Anti Aliasing I get 50-60 FPS mind you with clouds. Why is this when I can run Rise of the Tomb Raider at 2.5k resolution and max settings and get 40-50 fps and this is giving me 20 just like XP10?

 

And yet I am the only one here with AMD so I should get better performance because of Vulkan...
0 votes
answered by (28 points)
For your information:

I tested  the performance for x-plane 11 with Windows 7 and Ubuntu 16.04 LTS  and the result is much better for Linux. I reach about 30 fps and the system is only i5-2500, GTX660 and 16GB RAM. With Windows 7 it's only a slide show.
commented by (80 points)
Last updates of X-11 has given great improvement, my fps has grown from 19 to around 35 fps. Ung gtx 1080 Aero 1 000 Ghz on 8 core i7 4,6 mhz motherboard.

Good job

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