Basic specs: This is a 5900 RPM drive, rated at 95MB/s max transfer rate and <16ms access (per the product manual). The power consumption is 3.0W idle and an an amazing 19dBA/20dBA noise--per the specs.
To be honest, I wasn't expecting much after having disappointing (atrocious?) performance from WDC's "green" drives. As far as performance, however, I was pleasantly surprised. This drive tops out at 120MB/s--way above spec. The AVERAGE is 95 MB/s. Also, I was expecting access times (including rotational latency) to be well above 20ms. However, here again, I was pleasantly surprised with 14.7ms--way above spec.
OK, here's where I drop the bomb. I have no idea what kind of drugs Seagate was on when they came up with the acoustics. It is on their website, their datasheet, and the product manual. I have been impressed with past Seagate drives over their quietness, so I was really hoping this would be a very quiet drive at its rated 19dB which is even low for laptop drives. In fact, the low noise is the main reason I bought this. I didn't buy it for performance. I have SSDs and VelociRaptors for that. This is a media drive. And, the noise is obnoxious. This two-platter drive is louder than my 7200 RPM 4-platter Seagates. It is also louder than my VelociRaptors. The noise is also far worse than rated because it is a very high-pitched whine. About the closest I can think of is the old WDC Raptor 10K RPM drives.
As a final note, my Watt-Meter measured about a 4W difference between plugged in and not. This is at the wall, so considering power supply efficiencies, 3W or so is believable which is very low power.
In sum, this is a great drive for a file server that is far away in a closet somewhere. Its performance is good, and it is low power. Unfortunately, for a desktop or media center PC, the noise will give you a headache. There are better drives for those applications, like the older, quieter, 7200 RPM Seagates for starters. For any application where the drives sleep when not used, any power savings with this drive is just not worth the noise.