Bottleneck calculator

What a bottleneck is

A bottleneck is the part of your PC that sets the pace. In a game, the processor prepares each frame and the graphics card draws it. Whichever finishes last decides your frame rate. If the processor is slower, it is a CPU bottleneck and the graphics card idles part of the time. If the graphics card is slower, the card is the limit and the processor has spare capacity.

Every PC has a limit somewhere, so a bottleneck is not a fault in itself. A graphics card that is the limit is normal and is what you want for gaming at 1440p or 4K. A processor that holds back an expensive card by more than 15 or 20 percent is the case worth fixing.

How we calculate it

We take the usable speed of the processor and compare it with the work the graphics card can do at the resolution you choose. The result is a percentage showing how much of the stronger part goes unused, and which part limits. Within 10 percent we call it balanced. A GPU-limited pair is labelled as such and needs no fixing. A CPU-limited pair is rated mild, moderate or severe.

Resolution changes the answer a lot. At 1080p a fast graphics card often waits on the processor. At 4K the same pair is usually limited by the card. That is why you can try the three resolutions with the buttons.

How to fix a CPU bottleneck

You have three options. Raise the resolution or the graphics settings, which moves work from the processor to the card and costs you nothing. Lower the settings that load the processor, such as crowd density, view distance and simulation detail. Or replace the processor, ideally with one on the same socket so you keep your motherboard. The tool lists processors that would balance your card.

Do not replace a processor because a calculator said so. If you play at 1440p or 4K and your frame rate is fine, there is nothing to fix.

Myths about bottlenecks

A Ryzen 5 3600 with an RTX 4070 loses about 17 percent at 1080p (a mild bottleneck) and almost nothing at 1440p or 4K, while a Core i3-12100F with an RTX 4080 loses about 45 percent at 1080p. Those two cases show how much the card matters. Three claims come up often and are wrong. "Any processor older than five years bottlenecks a new card": it depends on the resolution, and at 4K most older chips are fine. "A bottleneck damages the card": it does not, the card just waits. "You need to match the price of the two parts": price says little, and cache size, core speed and the games you play say more. Use the resolution buttons on the calculator to test your own case instead of relying on rules of thumb.