WD400JB
http://www.wdc.com./ch/products/Products.asp?DriveID=36
Fluid Dynamic Bearing (FDB) technology ?improves hard drive reliability; reduces heat, vibration, and noise.
WD200BB
http://www.wdc.com./en/products/Products.asp?DriveID=6
Fluid Dynamic Bearing (FDB) technology – improves hard drive reliability; reduces heat, vibration, and noise.