Is my CPU bottlenecking my GPU, or does X-Plane simply not load the GPU enough?

[Scramjet333 39]

Hi all, I'm currently simulating a flight as I type this post, and I notice my frame-rates wildly fluctuating. Below is a screenshot of my GPU load with X-Plane 10:

As you can see, the GPU is currently running at 967 MHz (seen along the top of the window), but its maximum frequency is 1.3 GHz (as seen where the cursor is pointing). The typical load voltage also ought to be 1.10 V rather than 0.96 V. This clock speed (and voltage) varies wildly as my flight progresses, and the GPU load bar, which is currently around at 50%, gives me a little inkling of what's going on, but I'm not sure. This is the scene that X-Plane is currently rendering:

The framerate counter is at the top right. My specs (the ones that matter, at least) are as listed below:

• Intel Core i7-4710MQ @ 2.5 - 3.5 GHz
• nVidia GeForce GTX 860M with 2 GB GDDR5 VRAM
• 16 GB 1600 MHz DDR3L RAM
• 1920 × 1080 13.3" display

The CPU is running at its full rated 3.3 GHz (rated speed when all four cores are loaded), but the CPU load isn't very high, either. What gives? I don't think there's a bottleneck, but better be safe than sorry. Have any of you experienced this behaviour on your systems? Does your GPU clock speed significantly throttle when X-Plane isn't doing very much?

[soaring_penguin 428]

2 things: in Nvidia settings, set your GPU Performance level to "Prefer Maximum Performance". This will make sure that your GPU is not switching back and forth between adaptive mode and Maximum performance modem.

Second thing: X-Plane 10 is running mainly on one core, so when your 1 of your 4 cores is maxed, CPU usage will be 25%.

[be77solo 125]

My machine behaves similar. When the CPU is being hit harder, the GPU clocks back a bit like you are seeing.

 

In your pic, the CPU at .025 is the limiting factor compared to the GPU at .024. The higher this number, the bigger that load XP is putting on either.

[Scramjet333 39]

My machine behaves similar. When the CPU is being hit harder, the GPU clocks back a bit like you are seeing.

 

In your pic, the CPU at .025 is the limiting factor compared to the GPU at .024. The higher this number, the bigger that load XP is putting on either.

Ah, OK, but there's nothing to load the CPU at all in that scene. I was crossing the English Channel, didn't have any orthophotos, W2XP roads, etc. Only HD Mesh was installed, and even then, the land around the Channel is generally flat. What's up?

[sizziano 172]

Ah, OK, but there's nothing to load the CPU at all in that scene. I was crossing the English Channel, didn't have any orthophotos, W2XP roads, etc. Only HD Mesh was installed, and even then, the land around the Channel is generally flat. What's up?

 

It's a laptop, don't expect miracles. What are your CPU and GPU temps while flying?

[Scramjet333 39]

It's a laptop, don't expect miracles.

Sigh... With all due respect, I feel that's a very antiquated mentality when it comes to performance notebooks... Modern ones built to a certain standard can definitely cool their components well (and still be powerful in the first place), unless companies do something really ridiculous like attempting to put a GTX 1080 in a nearly-ultrabook chassis (like the Razer Blade Pro, where performance is really more like a GTX 1070).

 

Nevertheless...

What are your CPU and GPU temps while flying?

My GPU temps can be seen in the GPU-Z screen shot in my first post. CPU temperatures are similar: around 65-75°C. X-Plane nearly never brings my components to anywhere remotely as hot as games like GTA V and The Witcher 3: Wild Hunt do, whereby my CPU regularly exceeds 80°C and GPU gets to 75°C at least. Even then, I generally don't see either throttling at all until they reach immense temperatures, which only happens when I cover up the bottom vents and leave things to run for an extended period of time.

[Longranger 148]

 X-Plane nearly never brings my components to anywhere remotely as hot as games like GTA V and The Witcher 3: Wild Hunt do, whereby my CPU regularly exceeds 80°C and GPU gets to 75°C at least.

Every flight simulator has the problem that a lot of work has to be done by a single CPU core, and this process is also responsible for the GPU dispatch. Furthermore X-Plane 10 was more or less written for simple  unified shaders. It only needs big GPU, since it needs a huge amount of VRAM, but it doesn´t need the real GPU power.

 

This will probably change a bit in X-Plane 11 with the new PBR shaders and features like tesselation for water and so on. That´s the main reason why the PBR renderers were so damn interesting. Moder GPUs were developed for shaders, like these..NVidia and AMD were the big sponsors for these features.within the 11 run X-Plane will probably start to support Vulkan, too, although it is unclear if the Vulökan Version would have advantages compared with OpenGL.

[sizziano 172]

Sigh... With all due respect, I feel that's a very antiquated mentality when it comes to performance notebooks... Modern ones built to a certain standard can definitely cool their components well (and still be powerful in the first place), unless companies do something really ridiculous like attempting to put a GTX 1080 in a nearly-ultrabook chassis (like the Razer Blade Pro, where performance is really more like a GTX 1070).

 

Nevertheless...

My GPU temps can be seen in the GPU-Z screen shot in my first post. CPU temperatures are similar: around 65-75°C. X-Plane nearly never brings my components to anywhere remotely as hot as games like GTA V and The Witcher 3: Wild Hunt do, whereby my CPU regularly exceeds 80°C and GPU gets to 75°C at least. Even then, I generally don't see either throttling at all until they reach immense temperatures, which only happens when I cover up the bottom vents and leave things to run for an extended period of time.

 

 

You want to look at core temps not package. And the fact remains that even if your components are col enough a 860M and a 4710MQ aren't ideal. Have you tried lowering some CPU bound settings?

[magnetite 38]

X-Plane nearly never brings my components to anywhere remotely as hot as games like GTA V and The Witcher 3: Wild Hunt do, whereby my CPU regularly exceeds 80°C and GPU gets to 75°C at least. Even then, I generally don't see either throttling at all until they reach immense temperatures, which only happens when I cover up the bottom vents and leave things to run for an extended period of time.

 

XPlane is a full world simulator. Really can't compare it to those games you listed. It's a different animal.

[jcomm 5,890]

And turn off threaded optimization in NI !