Noise levels were measured with an Extech 407727 Digital Sound Level meter 1" from the side of the drives at idle and under an HD Tach seek load. Drives were run with the PCB facing up.
Although it's a little louder than previous GreenPower drives under a seek load, the 2TB Caviar Green is as quiet as any other desktop drive we've tested at idle. What's more, its seek noise levels are two decibels quieter than the 1.5TB Barracuda, which is a noticeable margin.
For our power consumption tests, we measured the voltage drop across a 0.1-ohm resistor placed in line with the 5V and 12V lines connected to each drive. We were able to calculate the power draw from each voltage rail and add them together for the total power draw of the drive.
Perhaps even more impressive than the Caviar Green's low noise levels is the drive's frugal power consumption. The 2TB Green actually consumes less power than the original Caviar GP at idle, and about the same under load. Sure, the 1TB Caviar Green pulls fewer watts, but it's only spinning three platters and half the capacity. If you factor in the new Green's whopping 2TB of storage, the drive delivers by far the lowest power consumption per gigabyte at both idle and under load.