Although PCs have steadily grown more energy efficient over the last few years, there's still room for improvement. We tried to find out how you can make a Haswell system as efficient as possible. We first tried using different components, then attempted tweaking various (BIOS) settings, and finally tried undervolting.
Slow computer got you down? Maybe a hardware upgrade should be in your cards, if so this guide to the Fundamentals of Upgrading a PC is an invaluable read. PCSTATS Tips