SFR Speed Test

This page helps users of SFR (Société Française du Radiotéléphone) understand their internet speed test results. Whether you are on the premium SFR Box 8X fiber plan or the widely used THD (Coax) network, verifying your connection stability is critical.

SFR manages two distinct high-speed networks in France: true Fiber (FTTH, up to 8 Gbps) and Coaxial Termination (FTTLA/THD, up to 1 Gbps), which behave very differently in speed tests.

How to interpret your SFR results

A SFR speed test measures three core metrics:

Download speed:
- SFR Fibre Power (Box 8): Expect 900+ Mbps on wired connections. The Box 8X can deliver up to 8 Gbps if you have compatible 10G equipment.
- SFR THD (Coax): Usually stable at 800-940 Mbps depending on your zone.

Upload speed: This is the main difference.
- Fibre (FTTH): High upload speeds (500 Mbps to 1 Gbps).
- THD (Coax): Capped lower, typically between 40 Mbps and 100 Mbps.

Ping (Latency): Essential for gaming. Fiber connections usually offer 5-15ms. THD connections may be slightly higher (15-25ms).

SFR Box Login – Default IP & Access

Access your SFR Box interface to change WiFi channels, separate 2.4/5GHz bands, or view line diagnostics.

Connecting to Administration

1. Ensure you are connected to your SFR Box WiFi or LAN.
2. Enter 192.168.1.1 in your browser bar.
3. Click on the "Maintenance" or "WiFi" tab.
4. Hold the WPS button on the physical box when prompted to authenticate.

Common Causes of Slow SFR Speeds

"Voyant PON" Blinking Red: This is a critical error on Fiber connections. It means the Optical Network Terminal (ONT) cannot see the network. Typical causes are a disconnected fiber cable (check the green connector) or a general outage in your neighborhood.

WiFi Saturation: In dense apartments, the 2.4 GHz band is often unusable. Log in to your box and force your devices to connect to 5 GHz for better speeds.

Box 8X 10G Port: If you are paying for the "8 Gbps" offer but only getting 1 Gbps, ensure you are plugged into the specific 10G LAN port (often distinguished by a grey mark) and using a Cat6a cable. Ordinary LAN ports are capped at 1 Gbps.

When to contact SFR Support (1023)

Contact Customer Service if:

The "PON" or "S" (Sync) light remains red or flashing for more than 30 minutes.

Your speed test result is consistently below 30% of your advertised speed on a wired connection.

You have physical damage to the white fiber optical cable.

SFR Fibre Competitors

If you are exploring alternatives in France, consider testing these networks:

• Orange Speed Test: The historic operator with the largest Fiber footprint (Livebox).
• Bouygues Telecom Speed Test: Known for the Bbox Ultym and WiFi 6E performance.
• Free Speed Test: Offers the unique Freebox Ultra with speeds up to 8 Gbps.

SFR Speed Test FAQs

What does a blinking red 'PON' or 'S' light mean on my SFR Box? A blinking red PON (Fiber) or 'S' (THD/Coax) light indicates a loss of signal. This means your SFR Box is not receiving internet from the network. Check if your fiber cable (green tip) is securely plugged in. If the light persists, it likely indicates a network outage.

Why is my upload speed low on SFR THD? SFR "THD" (Très Haut Débit) offers use coaxial cable technology, which is inherently asymmetric. While download speeds can compete with fiber (1 Gbps), upload speeds are technically limited to around 60-100 Mbps, unlike true FTTH fiber which can offer 500+ Mbps upload.

How do I login to my SFR Box interface? Open a browser and type http://192.168.1.1. To authenticate on modern boxes (Box 7, 8), you usually press the physical 'WPS' button on the front of the box for 5 seconds until the LED flashes to confirm access.

How can I test the full 8 Gbps speed of SFR Box 8X? The SFR Box 8X offers up to 8 Gbps shared speed. To test speeds above 1 Gbps on a single device, you MUST use the dedicated 10G LAN port and a PC with a high-speed 10GbE network card. Standard Gigabit ports will cap your test at ~940 Mbps.