PC Bottleneck: What It Is and How to Find Yours

What Is a Bottleneck?

In PC gaming, a bottleneck occurs when one component cannot keep up with another's output, limiting overall system performance. The two most common bottlenecks are: CPU bottleneck: The CPU cannot process game logic and feed the GPU fast enough. GPU usage stays below 90%; CPU usage maxes out. FPS is lower than expected for your GPU. GPU bottleneck: The GPU cannot render frames fast enough. GPU usage is 98–100%; CPU is below 80%. FPS is limited by rendering throughput.

Identifying Your Bottleneck

Use MSI Afterburner (free) with the RivaTuner OSD to monitor GPU % and CPU % simultaneously during gaming.

• GPU at 95–100%, CPU at 50–80%: GPU bottleneck (normal and acceptable)
• CPU at 90–100%, GPU at 50–80%: CPU bottleneck (common in CPU-heavy games like Tarkov, BG3, MSFS)
• Both at 50–60%: Not a bottleneck — something else is limiting performance (RAM bandwidth, storage, thermal throttling)

The "Bottleneck Calculator" Websites

Sites like PC-Builds.com and gpucheck.com offer "bottleneck calculators." These are estimate tools based on benchmark databases, not precise measurements of your specific system and game. Use them as rough guidance only.

Acceptable vs Problem Bottlenecks

A GPU bottleneck is normal and desirable in gaming — you want the GPU at 100% because that means it is fully utilized. A CPU bottleneck in CPU-heavy games can often be improved with optimization (power plan, process priority, background process management) before buying new hardware. MrGameFix diagnostics include a bottleneck analysis as part of the optimization process.