How to Check for a Bottleneck on Your PC (Step-by-Step)

Why monitoring beats guessing

The cleanest way to know whether your PC has a bottleneck is to watch it work. A calculator like ours gives you an estimate. Real-time monitoring tells you what is actually happening in your favourite game, in your favourite scene.

What you need

• MSI Afterburner + RivaTuner for an on-screen overlay (free).
• Or Windows Task Manager (Ctrl + Shift + Esc) → Performance tab.
• A demanding game running for 10-15 minutes.

The 4 patterns to watch for

1. CPU near 100%, GPU under 75%

Classic CPU bottleneck. The processor cannot prepare frames fast enough, so the GPU sits idle. FPS dips and 1% lows tank.

2. CPU under 60%, GPU at 95-100%

You are GPU-bound. This is normal at 1440p, 4K and ultra settings. Lower the preset or enable DLSS/FSR if FPS is too low.

3. Both at 100% with low FPS

Likely thermal throttling or VRAM saturation. Check temperatures with HWInfo64.

4. Both under 70%, FPS still capped

V-Sync, frame cap, or a power-management problem. Disable caps and switch the Windows power plan to Ultimate Performance.

Frame time matters more than average FPS

Average FPS hides stutter. Watch the frame time graph: a flat line is silky gameplay; tall spikes are perceived stutters even when the average looks fine.

Cross-check with the calculator

Once you have a hypothesis from monitoring, plug your CPU + GPU + resolution into the bottleneck calculator and see if the predicted limiter matches what you observed. If it does, the upgrade path is clear.

Want to dig deeper?

• CPU vs GPU bottleneck: how to tell
• Why FPS drops on high-end PCs
• Frame pacing & 1% lows explained