Server farm and method for operating the same

A server farm comprising:

• a plurality of servers operably connected with each other;
• one or more processor operably connected with the plurality of server, the one or more processor being arranged to
• receive a job request of a computational task to be handled by the server farm;
• determine, from the plurality of servers, one or more servers operable to accept the job request;
• determine a respective effective energy efficiency value associated with at least the one or more servers, the respective effective energy efficiency value being defined by:
• a service rate of the respective server divided by a difference between an energy consumption rate value when the respective server is busy and an energy consumption rate value when the respective server is idle;
• and
• assign the computational task to a server with the highest effective energy efficiency value;
• for maximizing energy efficiency of the server farm, defined by a ratio of a long-run expected throughput divided by an expected energy consumption rate value.