Bottleneck basics

CPU bottleneck vs GPU bottleneck

A bottleneck is the part of the system that limits the final result. In games, the limiter often moves between the CPU and GPU depending on resolution, graphics settings, refresh rate target, game engine, background tasks, and drivers.

What a CPU bottleneck looks like

A CPU bottleneck usually appears when the processor cannot prepare frames quickly enough for the graphics card. This is common in high-refresh 1080p gaming, simulation games, large multiplayer matches, and games with heavy physics or AI.

• GPU usage stays below expected levels while frame rate is capped by the game loop.
• Lowering graphics quality does not improve FPS much.
• Frame times feel uneven even when average FPS looks acceptable.

What a GPU bottleneck looks like

A GPU bottleneck appears when graphics rendering is the slowest part of the frame. This becomes more likely at 1440p, ultrawide, 4K, high texture settings, ray tracing, or heavy anti-aliasing.

• GPU usage stays high while the CPU has headroom.
• Lowering resolution or graphics settings improves FPS.
• VRAM pressure can cause stutter, texture pop-in, or large frame-time spikes.

Why the answer changes by resolution

At 1080p, a strong GPU can finish frames quickly and wait for the CPU. At 1440p or 4K, the GPU has more pixels and effects to process, so the same build can become GPU-limited. This is why a single bottleneck percentage without resolution context is usually misleading.

Use the BottleneckRadar calculator to estimate a build, then run the live scan on the actual machine to check browser-side CPU, GPU, memory, and network behavior.