Why CPU limit fps?

[khjhpopasa]

Why cpu limit fps?
you can see in this video CPU usage only 50% so why it isn't load more to get max fps in same CPU?
1700X use only 50% and get so low fps to compare 5600X
How it possible?

 

[Gwenved]

Why cpu limit fps?
you can see in this video CPU usage only 50% so why it isn't load more to get max fps in same CPU?
1700X use only 50% and get so low fps to compare 5600X
How it possible?

Hi, it seems it is what the CPU is able to send to the GPU, not its work.

 

[Toothless]

Why cpu limit fps?
you can see in this video CPU usage only 50% so why it isn't load more to get max fps in same CPU?
1700X use only 50% and get so low fps to compare 5600X
How it possible?

Game isn't coded to use all CPUs, and instructions per clock on the 1700x are much lower than the 5800x.

 

[khjhpopasa]

Hi, it seems it is what the CPU is able to send to the GPU, not its work.

so how can I know if have limit from CPU ?
I meant in percent like this cpu limit on 62% is max for 4 cores?

Game isn't coded to use all CPUs, and instructions per clock on the 1700x are much lower than the 5800x.

up

 

[baris.saracli]

There are two important things about CPU and FPS. First, how many cores does a game utilize? Second, how strong is each core? In your case, if the game only uses 4 cores, your CPU usage will be about 50% in an 8-core CPU. So, if the cores are weak, your CPU won't produce enough fps.
Devil May Cry, for example, does not use more than 4 cores as far as I remember. As a result, a 4-core i3 processor can perform better than an 8-core FX because intel cores are stronger.

 

[Tatty_Two]

so how can I know if have limit from CPU ?
I meant in percent like this cpu limit on 62% is max for 4 cores?


up

If you can play the game and it's working as expected why worry? Lower resolution gaming (1080p and less) is more CPU bound so depending on the game the CPU may well be working harder than the GPU, once you get to 1440p it's the other way around, however resolution, the game (and it's detail settings) and graphics card play their part but you have not mentioned them, why does the CPU have to work harder if it is delivering the settings you have set such as refresh rate, visual quality and effects etc.

 

[anachron]

so how can I know if have limit from CPU ?
I meant in percent like this cpu limit on 62% is max for 4 cores?

Instead of CPU usage which depend on number of core in use as baris.saracli mentionned, you could start by checking your GPU usage. It should be closer to 100% if you are not CPU bound. It's obvious in the video.

 

[khjhpopasa]

There are two important things about CPU and FPS. First, how many cores does a game utilize? Second, how strong is each core? In your case, if the game only uses 4 cores, your CPU usage will be about 50% in an 8-core CPU. So, if the cores are weak, your CPU won't produce enough fps.
Devil May Cry, for example, does not use more than 4 cores as far as I remember. As a result, a 4-core i3 processor can perform better than an 8-core FX because intel cores are stronger.

If you can play the game and it's working as expected why worry? Lower resolution gaming (1080p and less) is more CPU bound so depending on the game the CPU may well be working harder than the GPU, once you get to 1440p it's the other way around, however resolution, the game (and it's detail settings) and graphics card play their part but you have not mentioned them, why does the CPU have to work harder if it is delivering the settings you have set such as refresh rate, visual quality and effects etc.

Instead of CPU usage which depend on number of core in use as baris.saracli mentionned, you could start by checking your GPU usage. It should be closer to 100% if you are not CPU bound. It's obvious in the video.

But if I see games that have CPU like 10700K with 3080 get 100fps for example and GPU is 100% it mean no limit from CPU , and another option 3700X with same graphics card and same 100% but he get only 92fps how it possible look like CPU doesn't limit here because GPU on max usage.
And still have gap for fps

 

[Vayra86]

But if I see games that have CPU like 10700K with 3080 get 100fps for example and GPU is 100% it mean no limit from CPU , and another option 3700X with same graphics card and same 100% but he get only 92fps how it possible look like CPU doesn't limit here because GPU on max usage.
And still have gap for fps

- Monitoring of stats is 'an estimate over time' and tied to a polling rate, so you won't always see the exact same numbers. Small differences are 'margin of error' - ignore them.
- Different architectures work differently together. Intel CPU might be better optimized for the task so it can feed the GPU better. The GPU might still have maxed utilization, but that is ALSO an estimate.

The % you see in on-screen monitoring are 'global' numbers, but you really are performance capped if ONE subsystem of your rig is maxed out. For example, if you are transporting the maximum number of bytes over the VRAM/system memory to feed the GPU, you will have 100% utilization on something and the GPU will do all it can, but you can still lose some FPS. You have to consider that we're talking 'Frames PER SECOND' here. An 8 FPS difference over 100 total FPS is just 8% of one second difference. We're talking about milliseconds here, so percentages are a very inaccurate way to display that.

Things you CAN check:

RTSS /Afterburner can do per-core CPU monitoring, also in games:

What you will probably see is that 1 or 2 cores are always going to be at 99% usage - even today many games still use one or two fat game logic threads and lighter ones alongside it. The performance is capped by the heaviest thread. In that case, improving the single thread CPU clocks will directly benefit gaming performance. This is a given and even DX12 with better threading doesn't completely remove that fact.

 

[khjhpopasa]

- Monitoring of stats is 'an estimate over time' and tied to a polling rate, so you won't always see the exact same numbers. Small differences are 'margin of error' - ignore them.
- Different architectures work differently together. Intel CPU might be better optimized for the task so it can feed the GPU better. The GPU might still have maxed utilization, but that is ALSO an estimate.

The % you see in on-screen monitoring are 'global' numbers, but you really are performance capped if ONE subsystem of your rig is maxed out. For example, if you are transporting the maximum number of bytes over the VRAM/system memory to feed the GPU, you will have 100% utilization on something and the GPU will do all it can, but you can still lose some FPS. You have to consider that we're talking 'Frames PER SECOND' here. An 8 FPS difference over 100 total FPS is just 8% of one second difference. We're talking about milliseconds here, so percentages are a very inaccurate way to display that.

Things you CAN check:

RTSS /Afterburner can do per-core CPU monitoring, also in games:

What you will probably see is that 1 or 2 cores are always going to be at 99% usage - even today many games still use one or two fat game logic threads and lighter ones alongside it. The performance is capped by the heaviest thread. In that case, improving the single thread CPU clocks will directly benefit gaming performance. This is a given and even DX12 with better threading doesn't completely remove that fact.

View attachment 180604

Thank for answer but I have another example

watch 0:40 sec RTX 3080 + 10700K how it possible GPU isn't 100%?
if minimal CPU nowadays it 4 cores and 10700K have 8 cores so it should be 50% of usage and with that GPU was 100% usage .
if you keep going on video he change from 1080p to 1440p and there the limit is off and GPU usage is 100%
how it possible for be only 30% instead 50% 8/2 = 4 => 50% usage for CPU in 1080p for max FPS

 

[Vayra86]

You can see in several examples that the CPU is single core limited. A great one is the Flight Simulator one around 12:30. The game uses one or two threads - all CPUs are about 25% utilized except the 2160p example where it dives just under 25%, and also shows lower FPS - there the bottleneck has shifted to the GPU. It goes to show there is ALWAYS a bottleneck. No system is perfectly balanced for every workload.

GPUs do get faster while CPUs have been stagnant for years.

Another element that is not hardware is just the games themselves - not all game logic and code can be executed with equal speed, so again: the slowest bits are holding back the parts that can go faster.

 

[spnidel]

so how can I know if have limit from CPU ?
I meant in percent like this cpu limit on 62% is max for 4 cores?

if your GPU is not maxed out, and your framerate is not capped - you most likely have a CPU bottleneck

 

[Tatty_Two]

And possibly because Mafia definitive edition does not need anything like the power of a 3080 and a 10700k I mean they recommend a 3770 and a GTX1080, it does not use the cores of the i7 10700k, just take a look at it's recommended specs, it is after all a DX11 game …...……….

Mafia: Definitive Edition | Mafia Games

Starring Tommy Angelo, Mafia: Definitive Edition is a complete overhaul of the original 2002 game, remade from the ground up.

mafiagame.com

 

[Mussels]

If you had a 4 core CPU, a game using two cores would show as 50% load.

You get to an 8 core, 16 thread CPU like mine and two cores being maxed out is around 12% - so a game can be CPU limited by being not designed to use more threads, whilst still appearing to use very little of a modern CPU.

TL;DR: some games only care about a small amount of fast cores, extras go to waste.

 

[khjhpopasa]

And possibly because Mafia definitive edition does not need anything like the power of a 3080 and a 10700k I mean they recommend a 3770 and a GTX1080, take a look at it's recommended specs, it is after all a DX11 game …...……….

Mafia: Definitive Edition | Mafia Games

Starring Tommy Angelo, Mafia: Definitive Edition is a complete overhaul of the original 2002 game, remade from the ground up.

mafiagame.com

And possibly because Mafia definitive edition does not need anything like the power of a 3080 and a 10700k I mean they recommend a 3770 and a GTX1080, take a look at it's recommended specs, it is after all a DX11 game …...……….

Mafia: Definitive Edition | Mafia Games

Starring Tommy Angelo, Mafia: Definitive Edition is a complete overhaul of the original 2002 game, remade from the ground up.

mafiagame.com

so that game use only two cores ? it possible in 2020 look so bad for game this year

edit:

show 100% usage on CPU 4 cores
it not clearly yet

 

[Vayra86]

Stop watching benchmarks and start playing. Gaming on PC has never been smoother in the history of gaming really, especially with the high refresh monitors and VRR tech we have now.

Games aren't about FPS counters and they won't give you the deep dive on how PCs work either.

 

[khjhpopasa]

Stop watching benchmarks and start playing. Gaming on PC has never been smoother in the history of gaming really, especially with the high refresh monitors and VRR tech we have now.

Games aren't about FPS counters and they won't give you the deep dive on how PCs work either.

I love that information like hobby moreover it curious me.
Do you know the reason? it very weird.

 

[Toothless]

I love that information like hobby moreover it curious me.
Do you know the reason? it very weird.

If you want information, start researching architecture differences between brands and generations. This isn't an overnight thing to learn and you've already got your answer from this thread.

 

[khjhpopasa]

If you want information, start researching architecture differences between brands and generations. This isn't an overnight thing to learn and you've already got your answer from this thread.

I do it anytime but still have last question issue .
comments #15 and #10

 

[Toothless]

I do it anytime but still have last question issue .
comments #15 and #10

Some games don't use all threads as said in post #3. Some use one, or two, or all. Some games it won't matter what hardware you give it just won't run well. Nothing in your control.

 

[Tatty_Two]

I do it anytime but still have last question issue .
comments #15 and #10

The low system specs requirement answers your question (relative to a 2020 game release), 16 threads in a CPU will not really help if the game is only able to use 2 or 4, recommended specs is a 4 core 8 thread Intel CPU that is now 7 generations old, posts 4, 5, 9, 11 and 14 answer your questions …… thread closed as I am getting dizzy again...……. research is the best way to further your knowledge if you would like to know more to feed your hobby.