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Is It Your CPU or Your GPU?

Pick your parts and the resolution you actually play at. This tells you which one runs out first, how large the gap is, and what to change before you spend money. Nothing is uploaded, nothing is installed, and there is nothing to buy on this page.

What a bottleneck actually is

Every frame is built in two stages. Your processor works out what exists this frame - where everything is, what is visible, what the physics did. Then your graphics card draws it. The frame is finished when the slower of the two finishes, so your frame rate is set by whichever one is behind. That one is the bottleneck.

This is not a fault. Every PC ever built has one side that runs out first, and the question is only whether the gap is small enough not to matter. A machine with no bottleneck at all would be a machine where both parts happened to finish at exactly the same moment, in every scene, in every game. That does not exist.

Why resolution changes the answer

This is the part most calculators leave out, and it is the part that matters most. Raising the resolution gives the graphics card more pixels to draw but does not give the processor more work - the game logic is identical at 1080p and 4K. So the same two parts can be processor-limited at 1080p and graphics-limited at 4K, and both readings are correct.

That is why the resolution field above is not optional, and why a percentage with no resolution attached to it is not an answer. It also means the cheapest fix for a processor-limited machine is sometimes to raise the resolution: you get a sharper image at the same frame rate, because the pixels were free.

Upscaling moves the load back

DLSS and FSR render fewer pixels internally and then reconstruct the image. That takes work away from the graphics card, so it shifts you back towards being processor-limited - which is why turning on Performance mode sometimes gives far less than expected. If you are already processor-limited, upscaling has little left to give you.

What this tool cannot tell you

It works from a relative performance model of each part at a given resolution. It does not know your memory speed, your temperatures, whether your memory profile is enabled, how much VRAM the game wants, or how the specific engine you play divides its work. Two people with identical parts get different frame rates for all of those reasons.

Treat the reading as a direction, not a measurement. The only real number comes from recording your own frame times - and the honest figure to watch is the 1% low, not the average, because the average hides exactly the stutter you can feel.