If your Ethernet connection is limited to 100Mbps (megabits per second) instead of the expected 1000Mbps (1Gbps), there could be several reasons for this. Here are some possible explanations:
Cable Limitation: One common reason for a limited Ethernet speed is the use of an older or incorrect cable. To achieve Gigabit Ethernet speeds, you need to use Category 5e (Cat5e) or Category 6 (Cat6) cables. If you're using an older Category 5 (Cat5) cable, it may not support Gigabit speeds and could be limiting your connection to 100Mbps.
Network Card Limitation: The network card in your computer or device may have a maximum speed of 100Mbps. Network cards are available in different versions, such as 10/100Mbps or 10/100/1000Mbps (also known as Gigabit Ethernet). If your network card only supports 100Mbps, it will restrict your connection to that speed.
Hardware Configuration: Some network devices, such as routers or switches, may have specific settings that limit the Ethernet speed. For example, certain switches have ports dedicated to 100Mbps connections. Check the settings of your networking equipment to ensure they are configured to support Gigabit speeds.
Duplex Mismatch: Ethernet connections can operate in half-duplex or full-duplex mode. If there is a duplex mismatch between your network card and the connected device (e.g., switch or router), it can result in reduced speeds. Ensure that both devices are set to the same duplex mode (preferably full-duplex for Gigabit Ethernet).
ISP Limitations: While less likely, it's worth checking with your Internet Service Provider (ISP) to ensure that your internet plan supports speeds higher than 100Mbps. It's possible that your ISP has imposed a speed limitation on your connection.
Verify Cable Quality: Ensure you are using a Cat5e or Cat6 Ethernet cable and that it is in good condition without any breaks or damage.
Check Network Card Properties: Right-click on your network adapter in the Device Manager (Windows) or Network Preferences (Mac), and verify that the speed is set to "Auto" or "1.0 Gbps."





