PC Bottleneck Calculator
Find out whether your CPU or your GPU holds your frame rate back. Enter what your PC did in a game. There is no percentage, because a percentage hides the game, the resolution, and the settings that decide the answer.
Test 1: usage while you play
Open Task Manager or an overlay such as MSI Afterburner. Play a demanding scene, then read the numbers.
Test 2: lower the resolution
Record FPS in the same scene at your usual resolution, then again one step lower with the same settings.
Fill in one test or both to see a result.
The cut points are rules of thumb, not measured constants. One game and one scene can differ from another. Nothing you enter leaves your browser.
How the verdict is decided
| Test | You see | Verdict |
|---|---|---|
| Usage | GPU at 95% or more, no CPU thread maxed | GPU-bound |
| Usage | A CPU thread at 90% or more, GPU under 85% | CPU-bound |
| Usage | Both near their limit, or the GPU between 85% and 95% with a maxed thread | Mixed |
| Usage | Neither maxed, or a frame cap was on | Inconclusive |
| Resolution | FPS up less than 10% at a lower resolution | CPU-bound |
| Resolution | FPS up 25% or more | GPU-bound |
| Resolution | FPS up between the two | Mixed |
If the two tests agree, that is the verdict. If one is inconclusive, the other stands alone. If they disagree, the result is mixed. These cut points are a rule of thumb from common troubleshooting practice. They are not an industry standard, and no benchmark data sits behind them.
Illustrative example, not a measurement: a game runs at 100 FPS at 1440p and 103 FPS at 1080p. The gain is 3%, under 10%, so the CPU is the limit.
How to use it
1. Record usage while you play
Open Task Manager or an overlay such as MSI Afterburner. In a demanding scene, note GPU usage and the busiest CPU thread.
2. Run the resolution test
Note FPS in one scene at your usual resolution, then again one step lower with the same settings.
3. Enter the numbers
Fill in one test or both. Two tests give a firmer answer than one.
4. Read the verdict
The result says CPU-bound, GPU-bound, mixed, or inconclusive, with the reason and the next step.
Common questions
What is a PC bottleneck?
A bottleneck is the part that stops the others from running faster. In games, the CPU prepares each frame and the GPU draws it. If the GPU waits on the CPU, the CPU is the bottleneck. If the CPU waits on the GPU, the GPU is.
Why does this tool show no bottleneck percentage?
A percentage needs a table of benchmark scores for every CPU and GPU, and the real answer changes with the game, the resolution, and the settings. A number from a table can look exact and still be wrong for your game. This tool uses what your own PC does in your own game instead.
How does the usage test decide?
As a rule of thumb, a GPU at 95% or more is the limit. A busiest CPU thread at 90% or more with the GPU under 85% points at the CPU. In between, the result is mixed. If neither is maxed, the limit may be the engine, RAM, or storage.
How does the resolution test decide?
Resolution mostly changes GPU work, not CPU work. If FPS rises by less than 10% after you lower it, the GPU had room and the CPU is the limit. If FPS rises by 25% or more, the GPU was the limit. These cut points are a rule of thumb, not a measured constant.
Why does a frame cap matter?
A frame cap or V-sync stops the game from using the full power of your parts, so both usage figures read low. The tool marks a capped run as inconclusive. Turn the cap off and test again.
Does a bottleneck mean I wasted money?
No. Every PC has a limit somewhere, and the limit moves between games and settings. A CPU-bound result at 1080p can turn GPU-bound at 4K. Use the result to choose the next upgrade or the next settings change.