Lower resolution and higher cpu load clarification

[salawow]

Hi

I read everywhere that lower resolution such as 1080p requires more CPU power than higher resolution such as 1440p. Honestly that's a concept that i can't wrap my mind around, so i'm asking for clarification about it. When playing at same refresh rate (let's say 60hz), it just seem intuitive that higher resolution are taxing the GPU more (since there's more pixel to render), without impacting the CPU (since we are asking the same amount of frames per seconds).

Can someone explain it to me ? Surely there's something i'm missing there, but what is it ?

Thanks

 

[feelinfroggy777]

When you play at higher resolution, the GPU has to work much harder to keep up. Therefore, it becomes the weakest link or bottleneck.

Think of it like eating. A lower resolution, the GPU can eat a whole lot of food (data) really fast cause it is easy. So the CPU has to work really hard to keep throwing out food to keep feeding it. But at higher resolution, the GPU cant eat as fast cause it is hard. So the CPU does not need to throw food out as fast to keep the GPU eating.

 

[TJ Hooker]

When playing at same refresh rate (let's say 60hz), it just seem intuitive that higher resolution are taxing the GPU more (since there's more pixel to render), without impacting the CPU (since we are asking the same amount of frames per seconds).

If you're getting the same FPS at either resolution then you're right, CPU usage is not affected. But changing the resolution will almost always have a significant impact on FPS. Lower resolution means your GPU can render frames faster, at which point your CPU will have to be able to keep up in order for your FPS to increase.

 

[salawow]

Thanks, i understand better now.

So if i got everything right, if i have let's say (random numbers) 80% CPU usage and 30% GPU usage at 1080p 60hz/60fps (capping at 60 with Vsync on), i would still have 80% CPU usage at 1440p 60hz/60fps (with Vsync on), however the GPU usage will be higher than before. That's right ?

 

[jaslion]

Thanks, i understand better now.

So if i got everything right, if i have let's say (random numbers) 80% CPU usage and 30% GPU usage at 1080p 60hz/60fps (capping at 60 with Vsync on), i would still have 80% CPU usage at 1440p 60hz/60fps (with Vsync on), however the GPU usage will be higher than before. That's right ?

You should indeed still see about 80% cpu useage then.