How to Check for Bottleneck in Your PC (CPU or GPU Performance Test Guide)

If your games lag, FPS drops, or GPU usage seems low even with powerful hardware, you may be facing a bottleneck in your system. Learning how to check for bottleneck in your PC can help you identify which component — the CPU, GPU, or RAM — is limiting performance.

In this guide, we’ll explain how to test, analyze, and fix bottlenecks to achieve the best possible gaming performance or rendering speed.

What Is a Bottleneck?

A bottleneck happens when one part of your PC is much slower than another, causing performance loss. Your CPU and GPU need to work together efficiently — when one lags behind, the other can’t perform at full capacity.

There are two main types of bottlenecks:

• CPU Bottleneck: The processor can’t keep up with the GPU, limiting graphics performance.
• GPU Bottleneck: The graphics card is slower than the CPU, capping your frame rate.

Why You Should Check for Bottleneck

Checking for bottlenecks helps you:

• Optimize your gaming PC performance
• Avoid wasting money on mismatched components
• Know whether to upgrade your CPU or GPU
• Achieve smoother gameplay and higher FPS

When you check for bottleneck, you’ll know if your PC setup is balanced or if one part is slowing everything down.

How to Check for Bottleneck in a PC

There are two main ways to identify bottlenecks:

1. Using real-time performance monitoring software
2. Using an online bottleneck calculator

1. Use Performance Monitoring Software

Real-time monitoring shows you exactly how your CPU and GPU behave during gaming or heavy workloads. Here are the best tools to check for bottleneck on your PC:

a. MSI Afterburner

• Free and highly accurate performance overlay.
• Displays real-time CPU usage, GPU usage, FPS, and temperature.
• If your CPU usage is consistently higher than your GPU usage, it’s a CPU bottleneck.

b. HWMonitor

• Monitors your processor, RAM, and graphics card temperatures.
• Helps identify if your CPU is throttling due to heat (a hidden bottleneck cause).

c. Windows Task Manager

• Press Ctrl + Shift + Esc → Go to Performance Tab.
• Run your game or benchmark while observing usage.
• If CPU is maxed out but GPU is not, that’s a CPU bottleneck.

d. 3DMark or Unigine Heaven

• Run a GPU benchmark test.
• Compare your FPS and scores with online averages for the same hardware to see if your GPU is underperforming.

2. Use an Online Bottleneck Calculator

If you’re planning to build or upgrade your PC, an online bottleneck calculator is the easiest way to estimate performance imbalance.

• PC-Builds Bottleneck Calculator
• CPU Agent Bottleneck Test
• Build Redux Bottleneck Estimator

Steps:

1. Enter your CPU and GPU model.
2. Add your RAM size, resolution, and game type.
3. The tool shows a bottleneck percentage (e.g., “10% CPU bottleneck”).

Under 10% = Excellent balance
10–20% = Slight bottleneck (still okay)
Over 25% = Upgrade recommended

How to Interpret Bottleneck Test Results

Common Signs of a Bottleneck

• Sudden FPS drops in certain games
• Low GPU usage (below 80%) despite powerful hardware
• Stuttering or inconsistent frame pacing
• CPU usage constantly 100% in games
• High temperatures causing performance throttling

How to Fix Bottleneck Problems

1. Fixing CPU Bottleneck

• Lower in-game settings like shadows, draw distance, and population density.
• Overclock your CPU safely using tools like Intel XTU or AMD Ryzen Master.
• Upgrade to a CPU with higher clock speed and core count.
• Enable XMP in BIOS for faster RAM performance.

2. Fixing GPU Bottleneck

• Lower resolution or graphics settings (e.g., anti-aliasing, ray tracing).
• Enable DLSS, FSR, or XeSS to improve frame rates.
• Upgrade your graphics card if you’re playing at higher resolutions like 4K.

3. Fixing RAM Bottleneck

• Upgrade to at least 16GB DDR4 or DDR5 RAM.
• Ensure your memory runs at the correct frequency (e.g., 3200MHz+).
• Run games from an SSD for faster data streaming.

4. Fixing Storage or Thermal Bottleneck

• Replace old HDDs with SSDs.
• Improve cooling (add case fans, clean dust, reapply thermal paste).
• Ensure your PSU delivers stable power.

Best Free Tools to Check for Bottleneck

Frequently Asked Questions (FAQ)

1. How do I check for a bottleneck on my PC?

Use MSI Afterburner or Task Manager to compare CPU vs GPU usage. If one is maxed out while the other isn’t, that’s your bottleneck.

2. Can I check for bottleneck online?

Yes — use a GPU bottleneck calculator or CPU bottleneck test tool like PC-Builds or CPU Agent.

3. What is a good bottleneck percentage?

Anything below 10–15% is considered ideal and shows a well-balanced system.

4. Can software cause a bottleneck?

Yes — background apps, outdated drivers, or malware can affect CPU and GPU performance.

5. Does bottleneck affect FPS?

Absolutely. A bottleneck directly limits how many frames per second your GPU can render.

Final Thoughts

Knowing how to check for bottleneck is one of the most valuable skills for gamers, streamers, and content creators. It ensures your PC build runs efficiently and delivers the best performance possible without wasted potential.

By using tools like MSI Afterburner or online bottleneck calculators, you can quickly diagnose whether your CPU, GPU, or RAM is limiting performance — and fix it for smoother gameplay, higher FPS, and faster workflows.