When you install a fresh copy of Windows Server 2012 and configure it with the File Server role, the default Power Settings favor power efficiency over performance.
For this reason, even if you a few have high speed network interfaces and the best SSD storage out there, you might not be getting the best IOPS and throughput.
To get the absolute best performance from your file server, you can set the server to the "High Performance" power profile.
To configure this using a GUI, go to the Start Menu, search for "Choose a Power Plan" under Settings, then select the "High Performance" option.
To configure this from a command line, use "POWERCFG.EXE /S SCHEME_MIN".