So I have a 1080p monitor, so when i look into games im interested in, i go and see how my specs perform at that resolution. When I was looking at Marvel’s Spider Man, the reviewer said that the game was CPU bound at 1080p. I assumed this to mean that the GPU won’t be utilized much, however when I eventually bought the game, I had a consistent 80+% GPU utilization. What exactly does being CPU bound mean then?
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it means the cpu is what is limiting the game from going to a higher framerate not the GPU, its taking longer to figure out the AI and what to draw than it takes the GPU to draw it. If your GPU is still at 80% utilization at 1080p than you likely didn’t have as powerful a GPU as the reviewer.
“CPU bound” means that the game is limited in getting more frames by the CPU instead of the GPU. It doesn’t mean the GPU isn’t being used, but rather that the GPU being faster wouldn’t increase the FPS.
Think about what it means for the GPU to be at 80% utilization. Why not 100%? Both the CPU and the GPU are being used to produce the frames delivered to the screen and one of them will be the limiting factor. When your GPU is at 80% your CPU is at 100%, at least on one processing core.
The CPU and GPU are working on processing different parts of the game. Broadly speaking, the CPU takes the previous state of the game world (a bunch of variables, including things like the position of your character), combines this with the inputs you gave, and returns the state of the world in the next moment. E.g. if you pressed the key to initiate a jump, then the cpu will change Spiderman’s vertical coordinate (among other things). You can think of this as a rudimentary physics simulation. When it’s time to draw a new frame, the GPU then takes this information about the state of the game environment, and translates it into an image on the screen. So instead of “Spiderman is at coordinates (x,y,z)” you get to see what that looks like. In short, the CPU does physics while the GPU does graphics (this is is a bit of a simplification but it’s good enough).
Some games are more demanding on the GPU, while others ask more from the CPU. Typically, CPU-heavy games are those that require a lot of physics to be simulated at the same time. This includes simulation games like Civilization or Cities: Skylines, as well as open-world games like Red Dead Redemption 2 or Cyberpunk 2077. Basically anything that has a lot of stuff going on at the same time, and therefore many variables that need to be updated from moment to moment (including interactions between variables, like one character shooting another character). Spiderman is an open-world game so it makes sense that it could be CPU-bound.
Being “bound” to one resource or the other (e.g. CPU or GPU) refers to which of these things is the bottleneck or limiting factor that will determine the performance you’re getting. And that depends on the combination of the game, the settings you play at, and your system. If you have a beefy GPU with a crappy CPU, you’ll end up being CPU-bound more often, and vice versa.
So, if you’re CPU bound, that means your frame rate is being limited by the CPU. But that doesn’t have to mean you can’t pump your settings up any higher. See, only some graphics/game settings affect the CPU – namely those that determine how many things are being simulated at one time. That includes, for instance, the draw distance, mesh quality, particle effects, water simulations, hair simulations, etc. But it does not include things like the resolution, anti-aliasing, shader quality, etc., as those are all just about how nice the things that are being simulated look on screen. So as long as you still have headroom left on your GPU utilization, you can up those settings without taking a hit in performance.
You ever here the term “a chain is only as strong as its weakest link”? They’re saying the CPU is the weakest link for that specific game. And to be clear, there will always be a weakest link in your system. Your computer is like a factory assembling frames to display on your monitor, and it can only run as fast as the slowest “worker”. When a game is less graphically demanding, the GPU might be able to dish out its work really fast, but the CPU can’t keep up, so you’re only able to get a framerate that your CPU can handle, whereas if you had a better CPU (with the same GPU), you’d have a higher framerate.
The GPU is able to work faster than the CPU because the way the developers decided to make their particular game and on what hardware you have in your pc. So the GPU has to wait on the CPU to be done everytime
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