What is a CPU bottleneck and should you worry?
Every computer has a bottleneck. One part finishes its work before another, so the slower part decides how fast the whole system goes. That is not a design flaw - it is how computers work.
CPU-bound vs GPU-bound
- A system is GPU-bound when the graphics card is the limiting part. This is what most gamers want: the GPU runs near 100 percent and the CPU has headroom.
- A system is CPU-bound when the processor cannot feed the GPU fast enough. Lowering the resolution does not help, because the CPU still has to do the same amount of game logic work.
How to tell which one you have
- Play a scene at your normal settings and watch GPU usage.
- Lower the resolution dramatically.
- If FPS stays about the same, the CPU is the limit. If FPS jumps, the GPU was the limit.
When it actually matters
A mild CPU limit in one or two games is rarely a reason to upgrade. A severe, constant CPU limit across the games you actually play is a different story.
The ApexCore bottleneck tool
Open the bottleneck checker, choose your CPU and GPU, and it will compare their relative performance indexes and show where the balance sits - with the same honest caveats as the FPS calculator.