MTU size performance impacts

The MTU size of the network can have a large impact on performance.

The use of large MTU sizes allows the operating system to send fewer packets of a larger size to reach the same network throughput. The larger packets greatly reduce the processing required in the operating system, assuming the workload allows large messages to be sent. If the workload is only sending small messages, then the larger MTU size will not help.

When possible, use the largest MTU size that the adapter and network support. For example, on Asynchronous Transfer Mode (ATM) adapters, the default MTU size of 9180 is much more efficient than using a MTU size of 1500 bytes (normally used by LAN Emulation). With Gigabit and 10 Gigabit Ethernet, if all of the machines on the network have Gigabit Ethernet adapters and no 10/100 adapters on the network, then it would be best to use jumbo frame mode. For example, a server-to-server connection within the computer lab can typically be done using jumbo frames.