Overhead
- Your internet speed is measured in raw bits per second (bps), but real-world data transfer includes additional information like headers, acknowledgments, and error checking.
- TCP/IP, Ethernet, and other protocols add packet overhead, meaning some portion of the bandwidth is used for network management rather than your actual data.
- This overhead typically accounts for 5-15% of the total bandwidth, which explains why you rarely see a full 1 Gbps in speed tests.
Speed test client and server
ISP and firewall/network management and contention
- ISPs often use network shaping, congestion control, and peering agreements that affect speed.
- During peak times, ISPs may limit speeds slightly to ensure fair distribution of bandwidth among users.
- Your internal network/firewall may do the same
- Its best to test out of hours with just your test laptop plugged into the internet connection to give the best results