A method for operating a server to improve bandwidth efficiency in a computer network is disclosed. The server is operable to transmit files between a memory of the server and destinations on the computer network through a communication link having a finite bandwidth. The files are distinguishable by type and the server is provided with a rule set for prioritizing transmission of files by type. The method comprises monitoring a bandwidth usage of the communication link, and triggering application of the rule set when the bandwidth usage exceeds a threshold amount. The threshold amount is determined relative to the finite bandwidth. The method further comprises distinguishing between the files according to type, and prioritizing transmission of the files according to type and according to the rule set.