Why don't I have all the bandwidth?

If you're wondering why your network isn’t delivering the full 10Gbps or 20Gbps you expected, you're not alone. There are many reasons a speed test might show lower results — and they’re not always related to your server or hosting provider.

In this guide, we’ll break down the most common reasons behind limited bandwidth results and how to test your connection the right way.

1️⃣ The Speed Test Tool Makes a Difference

Not all speed testing tools are built to handle high-speed connections.

• Sites like speedtest.net were originally made for home internet testing — usually under 1Gbps.
• Many test servers on these platforms can’t handle 10Gbps+ traffic, even if your server can.

🧠 Tip: Use dedicated tools or well-known test servers that support high throughput, such as iperf3.

2️⃣ Server Performance Can Be the Bottleneck

Your connection is only as fast as the server you're testing against.

• CPU, disk I/O, or system overheads may limit actual transfer speeds.
• Single-threaded downloads (e.g., from a browser or wget) rarely reach full bandwidth.

🧠 Tip: Use multi-threaded benchmarking tools like iperf3 to better measure actual network capability.

3️⃣ How You Test = What You See

The method you use to test bandwidth can have a huge impact.

• A single connection often fails to saturate a fast line.
• Most browsers and simple tools don’t open enough parallel streams.

🧪 Try This: Use tools that allow multiple threads or parallel streams (e.g., speedtest-cli --parallel, iperf3 -P 10).

4️⃣ Distance & Routing Still Matter

Even with modern infrastructure, geographic distance introduces latency and reduces performance.

• A test from France to Los Angeles will always be slower than a test within the same region.
• Each additional hop on the network adds delay and potential packet loss.

🧠 Tip: For the most accurate results, test between servers located in the same datacenter or region.

🎯 Final Thoughts

Getting a consistent 10Gbps+ speed is difficult under real-world conditions — and that’s completely normal.

✅ Focus on using the right tools
✅ Avoid long-distance tests
✅ Don’t rely on single-threaded downloads

Understanding these technical limits helps set realistic expectations and ensures you’re testing things properly.

Updated on: 03/04/2025