How does bottlenecking work?

[xYowie]

For example, i play gta 5 with an i5 6500 and a gtx 1070. The i5 sits at 60% cpu usage, this is not a bottleneck but how much of the cpu is being used by the gpu and how much of it is being used by the game? Im a noob when it comes to how to the cpu works with games, do games use for example 30% cpu usage for the world loading and stuff and 30% for the gpu?

[Wyzzy Moon]

they GPU does not "use CPU"
The GPU is it's own CPU.
So the game uses both the CPU and the GPU separately.

for smooth gaming you need both, if one is super weak than it will hold the game back even though the other one has room to spare. That's what bottlenecking is.
You need both, if one can't get along, it'll hurt performance

[Zyndo]

22 minutes ago, Wyzzy Moon said:

they GPU does not "use CPU"
The GPU is it's own CPU.
So the game uses both the CPU and the GPU separately.

They aren't really separate when it comes to gaming... a CPU (among its other tasks) is going to relay all of the world information to your GPU to be drawn. It will instruct the GPU where everything is, what its doing, what its nature is, potential physics calculations, and so on. Depending on how the game is programmed, some of these tasks may be calculated by the GPU instead, but make no mistake. the GPU would have nothing to do without the CPU telling it what to do.

 

The CPU is ALSO responsible for calculating behaviors in game. AI, tactics, and executing all the other workings of the game that are not necessarily related to the "who", "what", "when", and "where" that is largely sent to the GPU for drawing/display. The CPU will also deal with the "why" things are happening.  Things that don't need to be drawn, or things that can't be drawn. These things still need to be calculated so that the game can go on. The CPU ALSO does those things.

 

The CPU is very capable of doing its job without a GPU (if you ignore the fact that you can't actually run a computer without some sort of VGA input). However the GPU would be completely inoperable in most situations without the CPU's direct instructions. There are scenarios outside of gaming where you can use a GPU as a compute chip like a CPU, and in those cases it often performs much better than a CPU, but they are very specific use-cases.


To answer the OP's question, there is no real way to tell as far as I'm aware. It can vary a lot from game to game depending on how CPU intensive it is. A game like Tomb Raider will have very little CPU workload going on, so much of what its doing is just feeding the GPU. On the other hand, a game like GTA V will have a lot more tasks for the CPU to complete, so it will require a higher percentage of its utilization to run its own tasks. Then there is FPS, in-game effects, and a whole slough of other variables that make this sort of thing too difficult to really predict or calculate.

[Wyzzy Moon]

1 minute ago, Zyndo said:

They aren't really separate when it comes to gaming... a CPU (among its other tasks) is going to relay all of the world information to your GPU to be drawn. It will instruct the GPU where everything is, what its doing, what its nature is, potential physics calculations, and so on. Depending on how the game is programmed, some of these tasks may be calculated by the GPU instead, but make no mistake. the GPU would have nothing to do without the CPU telling it what to do.

 

The CPU is ALSO responsible for calculating behaviors in game. AI, tactics, and executing all the other workings of the game that are not necessarily related to the "who", "what", "when", and "where" that is largely sent to the GPU for drawing/display. The CPU will also deal with the "why" things are happening.  Things that don't need to be drawn, or things that can't be drawn. These things still need to be calculated so that the game can go on. The CPU ALSO does those things.

 

The CPU is very capable of doing its job without a GPU (if you ignore the fact that you can't actually run a computer without some sort of VGA input). However the GPU would be completely inoperable in most situations without the CPU's direct instructions. There are scenarios outside of gaming where you can use a GPU as a compute chip like a CPU, and in those cases it often performs much better than a CPU, but they are very specific use-cases.


To answer the OP's question, there is no real way to tell as far as I'm aware. It can vary a lot from game to game depending on how CPU intensive it is. A game like Tomb Raider will have very little CPU workload going on, so much of what its doing is just feeding the GPU. On the other hand, a game like GTA V will have a lot more tasks for the CPU to complete, so it will require a higher percentage of its utilization to run its own tasks. Then there is FPS, graphical quality, and a whole slough of other variables that make this sort of thing too difficult to really predict or calculate.

Yes your right.
But the CPU has it's tasks and the GPU has it's tasks, and that was more what I meant.
ofcource the GPU has to be instructed by the CPU but the cpu also has things to do by itself.
And if we speak of a CPU intensive game it's often those things that the CPU has to do that cause a heavy load not the things it has to relay to the GPU if I'm correct.

[Zyndo]

20 minutes ago, Wyzzy Moon said:

And if we speak of a CPU intensive game it's often those things that the CPU has to do that cause a heavy load not the things it has to relay to the GPU if I'm correct.

That can vary significantly depending on how many fps you're getting. If you're playing a game at 30 fps, then your load is probably on a CPU intensive game (and depending on your GPU you may be bottlenecking). If you're playing a game at 130 fps, then your CPU is probably spending a lot more of its power fueling the GPU.