to increase hashrate, you need to mod your bios and edit your memory timings.  Also, underclock and undervolt to save electricity and overclock the memory.  Its not plug and play, but there many guides out there, youtube videos and bitcointalk posts.  You could always check my website there is a section on bios flashing.  at your own risk.  no one said it was easy but for a little effort you will get 30% more hashrate for less power usage.