Western Digital has a faster Caviar Black available, a 6Gbit/s SATA 1TB model.
WD's Caviar Black drives come in 2TB, 1TB, 750GB, 640GB and 500GB models and all use the standard 3Gbit/s SATA drive interface.The new 3.5-inch model's name is the WD1002FAEX, and it comes with a double speed 6Gbit/s SATA interface, along with the same 64MB cache and 7,200rpm spin speed as the other Caviar Blacks.
Its buffer to disk transfer rate is rated at up to 126MB/sec. The 3Gbit/s 1TB model is rated by WD at a 3Gbit/s buffer to host rate, meaning a direct transfer speed comparison is not readily available.
Amazon has the WD1002FAEX Caviar Black available for $119.99, but lists it as having a 3Gbit/s SATA interface. That's a mystery. WD's model descriptor for 3Gbit/s SATA 1TB Caviar Black is the WD1001FALS
Amazon has the WD1001FALS available for $99.99, but gives it a 32MB cache whereas WD's description says it has a 64MB cache. Something's out of synch here.
It looks like a Caviar Black transition to 6Gbit/s SATA is starting with the 1TB model the lucky first one. ®