Noise level of 10’000 rpm harddisks

I just bought a Dell Studio XPS, core i7 (2 weeks ago, maybe) and I was surprised by how quiet it was. It does roar to life when you first turn it on, but it quickly subsides to below average levels. The fan does ramp up a little in response to increased processing levels, but the only thing I've really pushed it with was Google Earth.

In general, if you want assurances for noise level, you'll have to DIY, and for that I recommend Silent PC Review. You could mod an OEM system by buying your own PSU, upgrading your heatsink, or pasting on antivibrational dampening foam (like Acoustipack), but you're better off building from scratch.

Some hard drives are quieter than others. Silent PC Review covers this quite thoroughly:

Until about two or three years ago, the majority of hard drives on the market used ball-bearing motors, which had a characteristic high pitched whine and other objectionable airborne noise. Since then, the industry has shifted to much quieter FDB (Fluid Dynamic Bearing) motors, with the result that most recent drives are significantly quieter than older drives ... All major drive manufacturers now use FDB motors in their current lineups. If you have a typical non-FDB drive that's more than a year or two old, the simplest way to achieve lower noise (and improved performance) is to swap it for a new drive, almost any new drive.

There are three other factors that affect drive noise:

• The number of platters in the drive
• The difference between idle and seek
• Automatic Acoustic Management (AAM)

They also recommend some drives, and strongly recommend 2.5" notebook drives for the best reduction in sound (other than switching to an SSD). There are also several techniques for dampening hard drive noise, many of which are listed here.