The M9T is highlighted by its capacity and physical size, but there's plenty of other engineering inside. The drive is notably quiet thanks to its use of NoiseGuard and SilentSeek technologies; it reportedly maintains 25 decibels while idle and 27 decibels during performance. It comes equipped with both ATA Security Mode and ATA S.M.A.R.T. features to keep the drive protected from anyone but the intended user. The Spinpoint M9T also comes equipped with standard head load/unload technology to keep it protected from internal physical damage, which is a consideration with any HDD.
I just got 4 x WD10SPCX (1TB, slim, 7mm) - just posted about them here
. I quite dislike their whoosh noise at idle ... I'm waiting on 3 x Samsung M9T 2TB to see how they compare.
Theoretically, a single M9T should actually be noisier at idle than 2 x WD10SPCX, because the former is 25 dBA and the latter is 20 dBA at idle, so two of them makes 23 dBA ... that is if (i) the specs are accurate and (ii) they were both measured in the same way. I don't trust manufacturer noise specs so I'll test myself.