Why does lowering the speed of the network adapter improve its transfer rate?

If you have your network interface duplex/speed set to Auto Detect then you may experience some problems.

Its best to adjust the duplex/speed setting to see what gives you the best results. You'll need to know what speed your network is running at.

If you get error messages such as "Disk Full" or "Delayed Write Failed" when saving to the network then you should adjust the setting for duplex/speed.

Right click on the local area network icon in "Network Connections".

Click on the Configure button and then the Advanced tab.

You need to locate the Duplex/Speed setting (it may vary for different network cards).

If your network is running at 10Mbps, for example, then you should set your card accordingly.

The reason that slower speeds sometimes improve the transfer rate is because you may have several different devices on your network that work at varying speeds so the network has to compensate more to include all the devices. Slowing the network interface card means more devices can get involved without compensation and without as many network data collisions.

Best way is to update you NIC, companies provide update for network card every 3-6 month to be updated with ather products(SWITCH,ROUTERS)techniq,speed and compatability.