Here I will show a sample configuration of an energy efficient workstation.
This build, in my view, will provide power efficiency and stability as well as good performance.
PSU - Any 80 Plus (and up - such as Bronze, Silver, Gold, Platinum and Titanium)
Top brands include: Corsair, Seasonic, Cooler Master, Thermaltake, Antec and others.
I would recommend Corsair AX series power supply (rated 80 Plus Platinum) as it would waste the least power.
CPU - Any Intel 4th Generation CPU which model ends on T.
I recommend i7-4765T as its TDP is at 35W. So at its full power it won't go beyond 35 watts.
Motherboard - Leading low watt brands include Asus, EVGA, Gigabyte and Asrock. A gaming motherboard will typically consume much more power than a mini-ITX motherboard.
I recommend Asus Z87i-PRO - good performance and low power.
RAM - There is a low voltage type of DDR3 called DDR3L which uses less power, also emits less heat. Brands include Kingston HyperX Lovo or Genesis and Adata XPG, among others.
I recommend Kingston HyperX LoVo - Kingston's special line of low voltage ram.
Hard Drive - Western Digital Caviar Green or Seagate Barracuda LP for HDD, Samsung 840 Series for SSD.
I would recommend a Samsung 840 EVO or PRO series drive.
Optical Drive - most optical disc drives are the same power, however a slim drive version will consume less power than the standard version.
Monitor - Any LED backlit LCD monitor, preferably with high Energy Star compliance. The smaller the size of the screen - the lower the power consumption. Here's a list of 18-22 inch monitors and their wattage.
