How to Test Your Fibre Speed
Are you getting what you pay for? A guide to running accurate speed tests and interpreting the results.
How to Test Your Fibre Speed: A Step-by-Step Accuracy Guide
Executive Summary
Most people run a speed test on their phone over Wi-Fi and then call their ISP to complain. However, a proper speed test requires a specific setup to eliminate local variables. This guide teaches you how to run a "clean" test that your ISP will actually accept as evidence of a problem.
The "Clean Test" Protocol
To get an accurate reading of your fibre line, you must bypass as many local factors as possible.
Step 1: Use an Ethernet Cable
Plug a laptop or PC directly into the router using a Cat5e or Cat6 cable. Testing over Wi-Fi only tests your Wi-Fi, not your fibre.
Step 2: Turn off Other Devices
Ensure no one else is streaming Netflix, downloading updates, or syncing cloud files during the test.
Step 3: Close Background Apps
Close all browser tabs except the speed test, and exit apps like Steam, OneDrive, or Dropbox.
Step 4: Choose the Right Server
Always test to a local server in your city (e.g., Johannesburg or Cape Town) first to establish your "base" speed.
Comparison: Speed Test Tools
| Tool | Best For | Pros |
|---|---|---|
| Speedtest.net | General Use | Most widely accepted by SA ISPs. |
| Fast.com | Netflix Performance | Tests specifically against Netflix servers. |
| Cloudflare Speed Test | Technical Detail | Provides jitter and bufferbloat data. |
| MyBroadband Speed Test | Local Context | Best for comparing against other SA users. |
Interpreting Your Results
- Download Speed: Should be within 90-95% of your advertised speed on a wired connection.
- Upload Speed: Should match your profile (e.g., 50Mbps for a 100/50 line).
- Ping: Should be <10ms for local servers.
Practical Checklist: Troubleshooting Low Speeds
- Restart your ONT and Router: The classic "unplug for 30 seconds" fix.
- Check your Ethernet Cable: Ensure it's not damaged and is rated for Gigabit speeds.
- Test at Different Times: Run tests at 8 AM, 2 PM, and 8 PM to check for peak-time congestion.
- Bypass the Router: If speeds are still low, plug your PC directly into the ONT (requires PPPoE credentials) to rule out a faulty router.
Next Steps
Not getting the speeds you pay for? It might be time to switch.
Related Guides
Frequently Asked Questions
Why is Fast.com slower than Speedtest.net?
Fast.com tests your connection to Netflix servers. If your ISP 'shapes' streaming traffic, Fast.com will show a lower speed than a general speed test.
My speed is fine but my internet feels slow. Why?
This is likely a Latency or DNS issue. Your 'pipe' is big, but the 'reaction time' is slow.
Should I use the ISP's own speed test?
It's a good starting point to see if the problem is within their network, but always verify with an independent third-party tool.
Next Steps
Ready to put this knowledge into practice? Use our tools to find the best fibre connection for your home or office.