Maximum Efficiency: Build A 25W Performance PC Using Core i5

Step 3: An Efficient Hard Drive

There are still a few components left to optimize: the main memory and the hard drive. We tried removing one of the two DIMMs, but since DDR3 memory uses less power than DDR2, the impact was extremely small—doubly predictable, since we were running the DDR3 at 1,333 MT/s and default voltage. However, we have room to drop consumption versus the Western Digital VelociRaptor in our reference system, since it was never designed to be a low-power component.

We received Toshiba’s newest 640GB 2.5” hard drive, the MK6465GSX, at about the same time we completed this review. Since its power consumption is among the lowest seen in today's hard drives, we decided to use it instead of a faster 3.5" desktop drive.

The 5,400 RPM Toshiba helped deliver additional power savings. System idle power went from 26W with the undervolted system on the 220W FSP power supply to as little as 23W. That put us under the 25W target for which we were aiming. The difference at peak load is only two watts, but we’re getting close to the accuracy limits of our measuring equipment at this point. The MX6465GSX is also available in 160, 250, 320, and 500 gigabyte capacities. A detailed review of the new 640GB drives will follow soon.

Of course, a solid state drive is also an option here, but the limited capacity would be an issue for most folks, and the increased cost would push the value of this build in the wrong direction. For that reason, a 2.5" mobile drive with more room for storage makes the best sense.