A question about bottlenecks...

nimaemrani

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Nov 14, 2014
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I have a hard time understanding something about bottlenecks.

I currently have a 4790k and 2x 1080TI SLI and I'm running at 1080p. Before you start telling me that I'm an idiot for not having a better monitor, I want to know the answer to this simple question: If the CPU can't handle frames at a 1080p resolution, then why do people say I need to go to a higher resolution? Won't the CPU perform poorly at a higher resolution as well, causing even lower framerates?

 

Dunlop0078

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Well first off that CPU should handle two 1080 ti's quite well at 1080p in a lot of games that aren't very cpu heavy and have good SLI support. It can certainly do 1080p 60fps maxed in pretty much anything, a single 1080 ti would.

To answer your question. A higher resolution results in less CPU usage because the GPU is under a higher load to render all those pixels versus 1080p, this causes frame rates to be lower and thus less draw calls are sent to the CPU resulting in more load on the GPU and less on the CPU when at higher resolutions. That is a simple explanation that I think is pretty much correct, this article I linked below goes in depth on draw calls.

https://medium.com/@toncijukic/draw-calls-in-a-nutshell-597330a85381
 

Dunlop0078

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Well first off that CPU should handle two 1080 ti's quite well at 1080p in a lot of games that aren't very cpu heavy and have good SLI support. It can certainly do 1080p 60fps maxed in pretty much anything, a single 1080 ti would.

To answer your question. A higher resolution results in less CPU usage because the GPU is under a higher load to render all those pixels versus 1080p, this causes frame rates to be lower and thus less draw calls are sent to the CPU resulting in more load on the GPU and less on the CPU when at higher resolutions. That is a simple explanation that I think is pretty much correct, this article I linked below goes in depth on draw calls.

https://medium.com/@toncijukic/draw-calls-in-a-nutshell-597330a85381
 

manddy123

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CPU has little to no effect on higher resolutions, that's because the main worker on those scenarios is the GPU, so the bottlenecks aren't(if at all) as significant at higher res, that's why.

It will, still, do all of the work as it already does, but increasing the res will only give you more pixels that isn't for the CPU to render.

In other words, if your CPU is capable of running your games @1080p, it will be capable of running them @4k, it's all up(mostly) to your GPU.
 

Dunlop0078

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That'a not necessarily true. If the GPU was your bottleneck then yes that would be true, however if the CPU is your bottleneck performance in terms of FPS may stay exactly the same at say 1440p than it was at 1080p. Depending on how much more load is on the GPU at the higher resolution versus the lower resolution.
 

nimaemrani

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Thank you for the answer. Also, great article!

 

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