How to tell if your CPU or your graphics card is the bottleneck

When a game runs badly, the first question is what to upgrade or change. The answer depends on which part is the bottleneck: the one that has to work the hardest and therefore sets the pace. If your graphics card is the limit, a faster processor will not help, and the other way around.

What a bottleneck is

Every frame needs work from both the processor (CPU) and the graphics card (GPU). The CPU prepares the scene: it runs the game logic, the physics and the instructions for drawing. The GPU draws the picture. Whichever finishes last decides the frame rate. If the GPU waits for the CPU, the CPU is the bottleneck. If the CPU waits for the GPU, the GPU is the bottleneck.

The resolution test

This is the simplest test and needs no special software.

1. Play a demanding scene and note the FPS.
2. Lower the resolution a lot, for example from 1440p to 720p. Keep all other settings the same.
3. Look at the FPS again.

If the frame rate rises clearly, the GPU was the limit, because you gave it fewer pixels to draw. If the FPS hardly changes, the CPU is the limit, because it still has the same amount of work to prepare.

Check usage in an overlay

Most graphics card tools and many monitoring programs show the usage of the CPU and the GPU while you play.

• If the GPU is at 95 to 100 percent and the CPU is lower, the GPU is the bottleneck. This is normal and good: you are using what you paid for.
• If the GPU is well below 90 percent and one or more CPU cores are near 100 percent, the CPU is probably the bottleneck.
• If neither is high, something else is limiting the game, such as a frame rate cap, V-Sync or slow storage.

Look at individual CPU cores, not only the total. Many games depend on one or two main threads. A processor can show 30 percent overall usage and still be the limit.

What to do if the GPU is the bottleneck

• Lower the resolution or use an upscaler. See how upscaling works.
• Lower expensive settings such as shadows and ray tracing. Our guide to the settings that cost the most shows the order.
• If you want a long-term fix, a faster graphics card helps.

What to do if the CPU is the bottleneck

• Lower settings that use the processor, such as view distance, crowd density and physics quality.
• Close background programs.
• Keep your system memory in dual channel mode and use its rated speed in the BIOS.
• If it is still not enough, a faster processor will help most in strategy games, large open worlds and high frame rate competitive games.

Why raising the resolution can be free

If your CPU is the bottleneck at 1080p, you can often move to 1440p with a small loss in FPS, because the GPU had spare capacity. Use our resolution FPS estimator to see how the pixel count changes.

Not every drop is a bottleneck

Stutter can also come from running out of video memory, a slow drive, overheating or a bad driver. If the average looks fine but the game hitches, look at frame time and 1 percent lows before you buy anything.

Before you spend money

1. Do the resolution test.
2. Check usage while you play.
3. Try the free fixes for the part that is limiting you.
4. Only then decide whether an upgrade is worth it, and match it to the real bottleneck.

A balanced system matters more than one very expensive part.