Older hardware
Older PCs or notebooks often do not have enough CPU power to process today's high data rates. The measurement is thereby not limited by the connection network of the provider but in the home network. As a guideline, cnlab recommends using hardware not older than three years for data rates of more than 500 Mbit/s.
The following table shows tested computers that have achieved a good or bad performance in various Gigabit tests. Bad performance results from hardware restrictions.
| Examples of PCs with bad Performance (PC not reach 1 Gbit/s) |
Macbook Air 6,2 |
W10 Lenovo S440 |
Old Versions of the Operating System
In addition to security risks, an old operating system can also impair your measured Internet performance. Old operating systems used outdated TCP/IP algorithms, which are not designed for today's fast Internet connections. If possible, you should update the operating system to the latest version. The following operating systems are out of date and are no longer supported by the manufacturer:
- Windows 7: Support for Windows 7 ended on January 14, 2020.
- Windows 8: Support for Windows 8 ended on January 12, 2016.
- Windows 8.1: Support for Windows 8.1 ended on January 9, 2018.
With Update 1, support is guaranteed until January 10, 2023.
Ethernet adapters
Many new notebooks have no RJ45 socket for direct connection of an Ethernet cable, but need an Ethernet adapter for connection. These adapters are not always suitable for Gigabit data rates. In addition to the Gigabit capacity of the adapter, the connection to the notebook is decisive as well. If the adapter is connected to a USB2.0 interface, the maximum data rate is limited to the USB2.0 transfer rate, i.e. to no more than 480 Mbit/s.
The following table shows the current and old USB standards with their maximum speed.
| Name / Version | Introduction | Description | Bitrate | Socket Color | Maximum Data Rate |
| USB 1.0 / 1.1 | 1996 | Low-Speed-USB (Low Bandwidth USB) | 1.5 Mbit/s | black | 1.2 Mbit/s |
| USB 1.1 | 1998 | Full-Speed-USB (Full Bandwidth USB) | 12 Mbit/s | black | 10 Mbit/s |
| USB 2.0 | 2000 | High-Speed-USB | 480 Mbit/s | black | 200 MBit/s |
| USB 3.0 | 2008 | Superspeed-USB | 4.8 Gbit/s | blue | -- |
| USB 3.1 | 2014 | Superspeed+-USB | 10 Gbit/s | blue | 7.2 Gbit/s |
| USB 3.2 | 2017 | USB 3.2 Gen 2x2 SuperSpeed | 20 Gbit/s | -- | -- |
| USB 4 | 2019 | USB 4 Gen 3x2 | 40 GBit/s | -- | 32 Gbit/s |
Antivirus software
Various antivirus programs permit monitoring of the network traffic. In this, the data traffic is reviewed for various patterns and contents and the data flow is influenced. This can have very negative effects on a speed test measurement. Some antivirus programs will lock the speed test entirely, while others use a local proxy to review the contents. This may lead to very low, as well as very high data rates. For optimal measurements, turn off your antivirus software during the test or configure an exception for the respective speed test program.
VPN (Virtual Private Network)
If a speed test measurement is carried out with the VPN switched on, the performance of the VPN and VPN provider is checked and not the Internet connection. VPN connections are usually not as powerful as the actual Internet connection. This leads to a longer path between the test client and the target server as well as to capacity bottlenecks and routing through different provider networks.