(Julius Neudorfer, TechTarget) Data center energy efficiency is the hot topic of the day. IT operators are working to quantify and improve the efficiency of their data centers, and that means improving server energy efficiency as well. Of course we all want the fastest, most powerful servers for our data center. Although energy efficiency (green!) is the buzzword, it seems that historically we think about energy usage only when our power or cooling systems are maxed out and need to be upgraded.

In the rush to optimize, virtualize and consolidate in the name of making computing-related operations more effective and efficient (and, of course, green), we've heard many server manufacturers profess that their products provide the most computing power for the least energy. Only recently have server manufacturers begun to discuss or disclose the efficiency of their servers. Currently there are no real standards for overall server energy efficiency.

There are several key components that impact the total energy consumed by a typical server: 
- Power supply
- Fans
- CPU
- Memory
- Hard drives
- I/O cards and ports
- Other motherboard components - supporting chip sets

These components exist in both conventional servers and blade servers, but in the case of blade servers, some items - such as power supplies, fans and I/O ports - are shared on a common chassis, while the CPU and other related motherboard items are located on the individual blades. Depending on the design of the blade server, the hard drives can be located on either the chassis or the blades.

In addition to the components listed above, OS and virtualization software impacts the overall usable computing throughput of the hardware platform.