Western Digital has built two internal hard drives for desktops. The Caviar black model is on the left and the RE4 is on the right in the picture above. The speed of the hard drives are 7200RPM and both drives have a 64MB cache with dual stage actuators. Both hard drives have a 3Gbps SATA interface and integrated dual processors. There is also a multi-axis shock sensor. The Caviar Black model costs $299 and the RE4 is awaiting an MSRP. Press release after the jump.