Hey all, I have yet another question to ask but fortunately this one is fairly quick. I've done a few searches already regarding just how CPU/GPU usage scales with change in resolution but keep getting contradictory answers at best and incomprehensible garbage at most. So to make a long story short what is the relationship between the three variables?
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Quick question: How does GPU/CPU scale with resolution?
- Thread starter Ws60
- Start date
I don't think there is a definitive answer to the relationship you are looking for. It would depend on how the program you are using is coded. Most modern games scale best with GPU performance as resolution increases. At a certain point (around 2560x1440p I think), VRAM can become a limiting factor if you have less than 3GB.
Nenu
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CPU scales with the games requirements and the GPUs requirements, and with efficiency of drivers.
Each game has different CPU requirements.
Each GPU has its own CPU requirements to max it out for a particular resolution, this depends on the visual quality settings of the game/GPU and the power of the GPU
A single GPU requires a small amount of CPU generally which rises up until the GPU is maxed out (for the same res/quality settings) or something else bottlenecks the system.
A more powerful GPU requires more cpu to max it out for the same res/quality settings.
Dual (or more) GPUs require more CPU than a single GPU, even if they are of the same total GPU power, SLI/Xfire has an overhead which increases with the number of GPUs.
As you raise resolution with the same hardware/settings, you increase the load on the GPU if it isnt already maxed out
If the framerate remains the same, the CPU load remains the same (ie if already using vsync or if the GPU was already maxed)
If the GPU becomes maxed out so that framerate is reduced, this "reduces" the load on the CPU.
If the GPU does not become maxed out and the framerate increases, the load on the CPU will increase and the load on the GPU will increase up until one of them maxes out or something else bottlenecks the system
To put it bluntly in general terms for the same hardware, up until one of these is maxed out:
Higher framerate = higher CPU load
Higher framerate and/or higher resolution = higher GPU load.
The limits on framerate will be either the CPU, GPU(s), vsync or some other bottleneck in the system.
Some bottlenecks could be:
Bus speed
Bus availability
System memory speed
Memory availability
Cache speed
Cache availability
GPU memory speed
GPU memory availability
Drivers
Interaction between drivers
Software/interaction between software elements.
Latency on any of the above which can be influenced by a whole load of things as well as the actual hardware.
That will do to start with
Each game has different CPU requirements.
Each GPU has its own CPU requirements to max it out for a particular resolution, this depends on the visual quality settings of the game/GPU and the power of the GPU
A single GPU requires a small amount of CPU generally which rises up until the GPU is maxed out (for the same res/quality settings) or something else bottlenecks the system.
A more powerful GPU requires more cpu to max it out for the same res/quality settings.
Dual (or more) GPUs require more CPU than a single GPU, even if they are of the same total GPU power, SLI/Xfire has an overhead which increases with the number of GPUs.
As you raise resolution with the same hardware/settings, you increase the load on the GPU if it isnt already maxed out
If the framerate remains the same, the CPU load remains the same (ie if already using vsync or if the GPU was already maxed)
If the GPU becomes maxed out so that framerate is reduced, this "reduces" the load on the CPU.
If the GPU does not become maxed out and the framerate increases, the load on the CPU will increase and the load on the GPU will increase up until one of them maxes out or something else bottlenecks the system
To put it bluntly in general terms for the same hardware, up until one of these is maxed out:
Higher framerate = higher CPU load
Higher framerate and/or higher resolution = higher GPU load.
The limits on framerate will be either the CPU, GPU(s), vsync or some other bottleneck in the system.
Some bottlenecks could be:
Bus speed
Bus availability
System memory speed
Memory availability
Cache speed
Cache availability
GPU memory speed
GPU memory availability
Drivers
Interaction between drivers
Software/interaction between software elements.
Latency on any of the above which can be influenced by a whole load of things as well as the actual hardware.
That will do to start with
That more or less fits with what I've read so far, ie that given the choice between a strong CPU/middling GPU and a middling CPU/strong GPU that the latter will generally have a greater impact on gaming performance then the former. Granted the ideal solution is a strong CPU/strong GPU but the realities of a budget can often prevent that.
It makes me wonder, as a thought experiment mind you, just how low you could actually go at 1440p before actually choking the GPU before it reaches ~100% load.
It makes me wonder, as a thought experiment mind you, just how low you could actually go at 1440p before actually choking the GPU before it reaches ~100% load.
Nenu
[H]ardened
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Depends on the game and the basic CPU needs of your hardware (ie xfire/SLI).
ie adding more GPUs on a CPU limited system will lower the framerate
Some quality settings can impact the CPU too.
ie adding more GPUs on a CPU limited system will lower the framerate
Some quality settings can impact the CPU too.
Dangman
Ninja Editor SuperMod
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- Dec 15, 2005
- Messages
- 46,056
As Nenu pointed out a few times already, different games have different CPU/GPU requirements. There are games where you're better off with a strong CPU/middling GPU than vice versa. With that said, from a longevity and cost-effectiveness standpoint, you're generally better off with the strong CPU/middling GPU route since it's lot easier and cheaper to upgrade a video card than to upgrade a CPU and motherboard and possibly even RAM now that we're only a year or two away from DDR4 RAM introduction. With a strong CPU, you can push back a CPU + mobo + RAM upgrade for quite awhile. For example, look at the Core i5 2500K: While there are certainly faster Intel CPUs these days, they're not that much faster to really justify an upgrade from the 2500K which had a MSRP of roughly $220. At around the same time as the 2500K was being widely introduced, you had the cheaper Phenom II X6 1055T CPUs or Phenom II X4 955 CPUs for around $100 to $150 give or take. Now look at those who own those AMD CPUs now: They're already having to upgrade to the newer FX CPUs or even Intel platforms for their new gaming PCs.