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.
Slower spindle speeds prove quieter in our noise level tests, particularly under load. There's little difference in noise levels between the 5,400-RPM drives, but the Momentus 7200.1 is close to a decibel louder than the Travelstar 7K100 when seeking.
Power consumption was measured for the entire system, sans monitor, at the outlet. We used the same idle and load environments as the noise level tests.
Power consumption results are very close among the 2.5" drives, with the 5,400-RPM models sipping a little less power at idle and under load. Seagate wins the seek power consumption sweepstakes here, but the Hitachi drives have lower power consumption at idle. Note that our 3.5" desktop drive consumes nearly 10W more under load than even the most power-hungry mobile drive.