Find bottlenecking?

[hak4fun]

Okay, so I know alot of people come and ask if there CPU is bottlenecking your GPU and usually the answers I see are just opinions. they look at the CPU, they look at the GPU and make a educated guess(or uneducated depending who it is) But couldn't we just ask for them to show us there MSI afterburner(or similiar) charts? The ones that show the GPU usage over time, and compare them against there CPU usage? Because if the CPU is at 100% and the GPU is jumping around everywhere instead of being at a fairly constant usage % then that shows that there is most likely a CPU bottleneck or a error somewheres else.

 

Is there a hole in my testing method?

[babadoctor]

the one hole: we're all too lazy

[Number]

the one hole: we're all too lazy

-___________-

[hawaiims]

Okay, so I know alot of people come and ask if there CPU is bottlenecking your GPU and usually the answers I see are just opinions. they look at the CPU, they look at the GPU and make a educated guess(or uneducated depending who it is) But couldn't we just ask for them to show us there MSI afterburner(or similiar) charts? The ones that show the GPU usage over time, and compare them against there CPU usage? Because if the CPU is at 100% and the GPU is jumping around everywhere instead of being at a fairly constant usage % then that shows that there is most likely a CPU bottleneck or a error somewheres else.

 

Is there a hole in my testing method?

Basically if you want to see if your GPU is bottlenecked, compare your results to someone testing that graphics card with a beast of a CPU and compare your framerate to that test. 

[babadoctor]

-___________-

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[Briggsy]

there have been hundreds, if not thousands of threads on this forum where people have posted their Afterburner graphs and asked what was going on. After you see enough of them, the answer becomes apparent when you see cpu Y paired with GPU X, and have already seen the evidence countless times to know beforehand whether there will be problems. 

 

This will change once directx12 is mainstream, but by then enough evidence will exist again to allow for fairly accurate guesses.

[hak4fun]

the one hole: we're all too lazy

Yea, but maybe we shouldn't be... One of these times we are going to give someone HORRIBLE advice because we didn't put the effort into it.

 

Basically if you want to see if your GPU is bottlenecked, compare your results to someone testing that graphics card with a beast of a CPU and compare your framerate to that test. 

True.

 

there have been hundreds, if not thousands of threads on this forum where people have posted their Afterburner graphs and asked what was going on. After you see enough of them, the answer becomes apparent when you see cpu Y paired with GPU X, and have already seen the evidence countless times to know beforehand whether there will be problems. 

 

This will change once directx12 is mainstream, but by then enough evidence will exist again to allow for fairly accurate guesses.

Hmm.... I see your point. As long as you are actually using your experience to give advice and not just picking numbers out your butt. Or being a fanboy idiot and simply saying "Your CPU is bottlenecking your GPU because well its AMD!"

[Faa]

CPU bottleneck; if the GPU operates at loads below 99% usage eg 50% (assuming vsync is off)
GPU bottleneck; you always want the GPU at maximum load for maximum performance - if it is and you're not happy with its performance reduce settings or upgrade

That's all about it. Don't bother monitoring the CPU usages, it's useless.

[hak4fun]

CPU bottleneck; if the GPU operates at loads below 99% usage eg 50% (assuming vsync is off)

GPU bottleneck; you always want the GPU at maximum load for maximum performance - if it is and you're not happy with its performance reduce settings or upgrade

That's all about it. Don't bother monitoring the CPU usages, it's useless.

Okay so if your CPU is bottlenecking your GPU it means that your CPU cannot proccess the data the GPU is trying to send and receive, correct?

So if your CPU is maxed out, it means it is doing everything it possibly can, correct?

If your GPU is happy, it is going to run at a constant performance, correct?

If that is all correct that means that if your CPU is running at 100% the whole time, and your GPU is going up and down and is defiantly not running at a constant performance your GPU isn't happy and most likely its your CPU. correct? Is there a error in my thinking?

[Faa]

Okay so if your CPU is bottlenecking your GPU it means that your CPU cannot proccess the data the GPU is trying to send and receive, correct?

So if your CPU is maxed out, it means it is doing everything it possibly can, correct?

If your GPU is happy, it is going to run at a constant performance, correct?

If that is all correct that means that if your CPU is running at 100% the whole time, and your GPU is going up and down and is defiantly not running at a constant performance your GPU isn't happy and most likely its your CPU. correct? Is there a error in my thinking?

The CPU doesn't need to be at 100% usage to form a bottleneck, like I said it's a useless indicator. Even if your CPU is at 100%, you still can have 99% usage on your GPU constantly so there's effectively no bottleneck.

Basically the CPU just tells the GPU what to do, if the CPU doesn't do that fast enough your GPU will be bottlenecked by the CPU. Your indicator is your GPU usage to monitor this, that's all there is to it.

[hak4fun]

The CPU doesn't need to be at 100% usage to form a bottleneck, like I said it's a useless indicator. Even if your CPU is at 100%, you still can have 99% usage on your GPU constantly so there's effectively no bottleneck.

Basically the CPU just tells the GPU what to do, if the CPU doesn't do that fast enough your GPU will be bottlenecked by the CPU. Your indicator is your GPU usage to monitor this, that's all there is to it.

No, if your CPU is at 100% and your gpu is at 30% and its flucuating alot then you have a bottleneck most likely, correct?

[i_build_nanosuits]

No, if your CPU is at 100% and your gpu is at 30% and its flucuating alot then you have a bottleneck most likely, correct?

yes...monitor your GPU loads while playing games with VSYNC off and you'll know if your CPU can fully utilise your GPU like Faa said...it's that simple.

[hak4fun]

yes...monitor your GPU loads while playing games with VSYNC off and you'll know if your CPU can fully utilise your GPU like Faa said...it's that simple.

Okay, thats all I was asking.

[i_build_nanosuits]

Okay, thats all I was asking.

As he said, a CPU not being fully ustilised in games is normal and it won't mean it won't bottleneck due to the fact that it can be too slow to process the required instructions to feed the GPU...which will end-up slowing down your graphics card (AKA CPU bottleneck)...but MOST OF THE TIME (not always) a CPU being completely pinned at 100% load (or even a single core pinned at 100% consistently) can most likely lead to bottleneck as well cause again some drawcalls will end-up being delayed or skipped and this will lead to either stuttering or GPU load going down (rendering slowed down)