Why lower FPS with higher resolution?

[Protomesh]

So I'm playing at 1920x1080 and GPU usage is between 19-26%.

 

But why do I get much higher FPS when I change the resolution to 1280x720 with GPU usage between 9-11%?

 

Why is creating a larger CPU bottleneck giving me more frames? I shouldn't lose FPS when I am not GPU limited yet I am losing FPS by increasing resolution and graphical settings?

 

Why would low textures give better FPS than high textures despite GPU having plenty of headroom?

[-rascal-]

4 minutes ago, Protomesh said:

So I'm playing at 1920x1080 and GPU usage is between 19-26%.

 

But why do I get much higher FPS when I change the resolution to 1280x720 with GPU usage between 9-11%?

 

Why is creating a larger CPU bottleneck giving me more frames? I shouldn't lose FPS when I am not GPU limited yet I am losing FPS by increasing resolution and graphical settings?

 

Why would low textures give better FPS than high textures despite GPU having plenty of headroom?

 

What GPU do you have / using?

If you are using some sort of Integrated graphics, it may be VRAM limited.

26%? 11% Are you using Windowed Mode, or Borderless, rather than Full Screen?

 

[PDifolco]

21 minutes ago, Protomesh said:

So I'm playing at 1920x1080 and GPU usage is between 19-26%.

 

But why do I get much higher FPS when I change the resolution to 1280x720 with GPU usage between 9-11%?

 

Why is creating a larger CPU bottleneck giving me more frames? I shouldn't lose FPS when I am not GPU limited yet I am losing FPS by increasing resolution and graphical settings?

 

Why would low textures give better FPS than high textures despite GPU having plenty of headroom?

What CPU ? GPU ? Game ?

Really can't tell anything with so vague claims

[Protomesh]

50 minutes ago, -rascal- said:

 

What GPU do you have / using?

If you are using some sort of Integrated graphics, it may be VRAM limited.

26%? 11% Are you using Windowed Mode, or Borderless, rather than Full Screen?

 

GTX 1060 and I'm on full screen. 

[Alex Atkin UK]

14 minutes ago, Protomesh said:

GTX 1060 and I'm on full screen. 

What game?  As it seems unlikely most games would not be using 90%, unless as others said its a VRAM limitation (quantity or bandwidth).

[Protomesh]

3 minutes ago, Alex Atkin UK said:

What game?  As it seems unlikely most games would not be using 90%, unless as others said its a VRAM limitation (quantity or bandwidth).

Not vram limitation but I can definitely double check tomorrow. It's an older game. I am CPU bottlenecked due to poor optimization.

 

So why am I losing FPS when increasing resolution or graphical settings? When I have GPU headroom?

 

CPU bottleneck shouldn't affect resolution.

[Mark Kaine]

kinda funny you automatically assume gpu when it could just as well be cpu.

 

but to answer the question,  because math, lower resolution typically results in higher fps,  because lower res uses less resources... as you already found out.

[Mark Kaine]

1 hour ago, PDifolco said:

What CPU ? GPU ? Game ?

Really can't tell anything with so vague claims

^this

[-rascal-]

19 hours ago, Protomesh said:

Not vram limitation but I can definitely double check tomorrow. It's an older game. I am CPU bottlenecked due to poor optimization.

 

So why am I losing FPS when increasing resolution or graphical settings? When I have GPU headroom?

 

CPU bottleneck shouldn't affect resolution.

 

What CPU, and what game?

Now that we know you have a GTX 1060.

Oh, GTX 1060 3GB or 6GB?

[Mark Kaine]

i think here's a fundamental misunderstanding 

 

CPU is responsible for frames, GPU only draws them.

 

so "CPU bottleneck shouldn't affect resolution" kinda makes no sense, because it *will* affect fps...

 

everything you describe hints at a CPU bottleneck, im afraid. 

[Sharkyx1]

22 hours ago, Mark Kaine said:

i think here's a fundamental misunderstanding 

 

CPU is responsible for frames, GPU only draws them.

 

so "CPU bottleneck shouldn't affect resolution" kinda makes no sense, because it *will* affect fps...

 

everything you describe hints at a CPU bottleneck, im afraid. 

I think you and the others are misunderstanding OP

 

My take on what he's saying is :

 

"I'm playing an older game and I'm cpu bound. I'm seeing very low GPU usage. Given those two things, why is my frame rate increasing at lower resolutions, when I'm already cpu bound at the higher resolution "

 

And I think the thing is, many games are capable of choosing to not render things that may be too small to see due to resolution. This would make the cpu load lower at lower resolution.

 

Other things I'm sure have an affect as well 

[Mark Kaine]

3 hours ago, Sharkyx1 said:

I think you and the others are misunderstanding OP

 

My take on what he's saying is :

 

"I'm playing an older game and I'm cpu bound. I'm seeing very low GPU usage. Given those two things, why is my frame rate increasing at lower resolutions, when I'm already cpu bound at the higher resolution "

 

And I think the thing is, many games are capable of choosing to not render things that may be too small to see due to resolution. This would make the cpu load lower at lower resolution.

 

Other things I'm sure have an affect as well 

im not misunderstanding it, but its difficult to explain... lowering res can improve performance even if you're cpu bound,  because yes that will lower the load even for cpu... the gains are just pretty limited and often it doesn't even help at all, but point is it can.

 

 

like extreme example: say you play at 1080p... cpu bound ...

 

lower it to "240p"... not cpu bound anymore... 

 

does that make sense?  cause that's how it works usually .

[starsmine]

On 1/17/2024 at 5:36 PM, Protomesh said:

So I'm playing at 1920x1080 and GPU usage is between 19-26%.

 

But why do I get much higher FPS when I change the resolution to 1280x720 with GPU usage between 9-11%?

 

Why is creating a larger CPU bottleneck giving me more frames? I shouldn't lose FPS when I am not GPU limited yet I am losing FPS by increasing resolution and graphical settings?

 

Why would low textures give better FPS than high textures despite GPU having plenty of headroom?

because your CPU bottleneck isnt 100% is one part, the other part is change of resolution DOES change the load on the CPU, its just not drastic

There are still frames that are GPU limited.

There ARE frames in this overlap that the GPU is the bottleneck, as you drop resolution the two spreads get further apart, but both go to the left. 

 

The average GPU frame time is say 16ms with a std dev of 5ms, with the cpu having an average of 22ms with a std dev of 6ms. aka with the assumption of iid (they are not iid it just simplifies the math greatly) that still means 10% of the frames are GPU limited. 

This is also why saying somthing is 40% bottlenecked by a part is not telling you as much as you think. 
like lets tighten up the standard deviations
16ms of GPU with std dev of 2ms, and a CPU at 18ms with a std deviation of 1 ms. 
the CPU bottlenecks the GPU around 90% of the time here as well like in the above example, but put in a new infinitly fast CPU you gain very little. cause all you have gone is from an average of 18 ms frame times to 16ms

[Mark Kaine]

love the graph! hahaha ... that's exactly what i meant! and exactly how this works too! : P

 

 

[Sharkyx1]

On 1/20/2024 at 6:12 PM, Mark Kaine said:

love the graph! hahaha ... that's exactly what i meant! and exactly how this works too! : P

 

 

I don't disagree with what you and the other guy are saying now. It was more just the way you said 

 

"everything you describe hints at a CPU bottleneck, im afraid."

 

When I made my comment I was responding mainly to that, because i was confused why you might make a point of that when he says he's cpu bound in the original post.

 

 

I've read the further responses since I made my first reply. I'm just attempting to clarify my meaning here