What's bottle necking?
- Thread starter nyxanna
- Start date
Solution
- Feb 22, 2015
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Bottlenecking, in terms of CPU-GPU pairing, *usually* means that a CPU is hindering the max. possible performance of a GPU. This will be evident if the CPU usage is at 99%-100% already while the GPU has not yet reached 99%-100%. You don't want that scenario.
In your case, the GPU is performing to its max. possible performance (given the resolution and graphics settings you are playing at) as shown in your screenshot "99%", while the CPU is not hindering your GPU's performance, using only "32%". This scenario is ideal.
There are several ways to get more FPS in a certain game, when your GPU is already at 99% usage:
1) Decrease your in-game graphics settings
2) Decrease your resolution
3) Get a more powerful GPU
In your case, the GPU is performing to its max. possible performance (given the resolution and graphics settings you are playing at) as shown in your screenshot "99%", while the CPU is not hindering your GPU's performance, using only "32%". This scenario is ideal.
There are several ways to get more FPS in a certain game, when your GPU is already at 99% usage:
1) Decrease your in-game graphics settings
2) Decrease your resolution
3) Get a more powerful GPU
geofelt
Titan
- Oct 9, 2006
- 54,374
- 4,185
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There is no such thing as "bottlenecking"
If, by that, you mean that upgrading a cpu or graphics card can
somehow lower your performance or FPS.
A better term might be limiting factor.
That is where adding more cpu or gpu becomes increasingly
less effective.
To see if your gpu is your limiting factor, try this test:
Run YOUR games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.
To see how sensitive your game is to single thread speeds,
imit your cpu, either by reducing the OC, or, in windows power management, limit the maximum cpu% to something like 70%.
Go to control panel/power options/change plan settings/change advanced power settings/processor power management/maximum processor state/
This will simulate what a lack of cpu power will do.
Conversely what a 30% improvement in core speed might do.
Be careful how you interpret task manager cpu utilizations.
Windows will spread the activity of a single thread over all available threads.
So, if you had a game that was single threaded and cpu bound, it would show up on a quad core processor as 25%
utilization across all 4 threads.
leading you to think your bottleneck was elsewhere.
It turns our that few games can usefully use more than 2-3 threads.
How can you tell how well threaded your games or apps are?
One way is to disable one thread and see how you do.
You can do this in the windows msconfig boot advanced options option.
You will need to reboot for the change to take effect. Set the number of processors to less than you have.
This will tell you how sensitive your games are to the benefits of many threads.
If you see little difference, it tells you that you will not benefit from more cores.
Likely, a better clock rate will be more important.
FWIW, sims, strategy and MMO type games tend to depend on the performance of a single master thread.
If, by that, you mean that upgrading a cpu or graphics card can
somehow lower your performance or FPS.
A better term might be limiting factor.
That is where adding more cpu or gpu becomes increasingly
less effective.
To see if your gpu is your limiting factor, try this test:
Run YOUR games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.
To see how sensitive your game is to single thread speeds,
imit your cpu, either by reducing the OC, or, in windows power management, limit the maximum cpu% to something like 70%.
Go to control panel/power options/change plan settings/change advanced power settings/processor power management/maximum processor state/
This will simulate what a lack of cpu power will do.
Conversely what a 30% improvement in core speed might do.
Be careful how you interpret task manager cpu utilizations.
Windows will spread the activity of a single thread over all available threads.
So, if you had a game that was single threaded and cpu bound, it would show up on a quad core processor as 25%
utilization across all 4 threads.
leading you to think your bottleneck was elsewhere.
It turns our that few games can usefully use more than 2-3 threads.
How can you tell how well threaded your games or apps are?
One way is to disable one thread and see how you do.
You can do this in the windows msconfig boot advanced options option.
You will need to reboot for the change to take effect. Set the number of processors to less than you have.
This will tell you how sensitive your games are to the benefits of many threads.
If you see little difference, it tells you that you will not benefit from more cores.
Likely, a better clock rate will be more important.
FWIW, sims, strategy and MMO type games tend to depend on the performance of a single master thread.
- Apr 16, 2011
- 281
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- 18,815
Thanks guys. I would just like to state that my GPU is the GTX 1080 and my CPU is the i5 4670K.
I always get told that my CPU should be bottlenecking the card but as you can see in the screenshot it looks like the opposite is the case here?
I always get told that my CPU should be bottlenecking the card but as you can see in the screenshot it looks like the opposite is the case here?
- Feb 22, 2015
- 4,102
- 92
- 39,040
The i5-4670K can handle such GTX 1080, depending on the CPU usage. If, for example, a certain game is very CPU-intensive, that may be a scenario why such CPU *might* hinder the max. possible performance of a GPU (which can be resolved by just OC'ing your CPU). In your case, it seems that the game is not CPU-intensive, hence, the "32%" CPU usage.
nukemaster
Titan
- Nov 23, 2004
- 19,626
- 6
- 74,965
Running max settings and tons of AA tends to make a CPU work pretty hard.
In MMO games, I find you will bounce back and forth sometimes the gpu will max(more quiet areas) others the cpu will(large scale battles).
It is important to know when the cpu maxes it may not be showing high percentages on some games. for example if a game only uses 2 cores a 4 core cpu can be "maxed" out in that game at only 50 percent usage(since 2 cores are simply not used). This will vary from game to game. It is easy to see because the gpu use will drop as will the frame rates.
In MMO games, I find you will bounce back and forth sometimes the gpu will max(more quiet areas) others the cpu will(large scale battles).
It is important to know when the cpu maxes it may not be showing high percentages on some games. for example if a game only uses 2 cores a 4 core cpu can be "maxed" out in that game at only 50 percent usage(since 2 cores are simply not used). This will vary from game to game. It is easy to see because the gpu use will drop as will the frame rates.
Roland Of Gilead
Titan
- Aug 8, 2008
- 10,341
- 2,266
- 77,690
that is literally the most complicated explanation I've ever read to describe a CPU/GPU bottleneck, or any other hardware limiting bottleneck (oh wait, I forgot, there's no such thing as a bottleneck!
) that 'might' hold back a system in one metric or another.I'm experienced enough with PC building, love learning about high end hardware (and low to mid end hardware too!) I've had to re-read your post a number of times to establish exactly what your trying to tell the OP.
Kudos @rasionjohn. Good answer. Helpful.
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