Legacy model of the Xbox 360 Development Kit. This XDK is using a Zephyr motherboard. The Legacy XDK used Xenon, Zephyr, Jasper, and Tonasket motherboards, skipping Falcon. Because it's the legacy XDK, it's configured with 512MB of ram, unlike the 1GB in the XDK-GB models.
Comes with a Sidecar, which is used for debugging / DVD emulation. It also stores the HDD.
Full Development kit bootloaders allow kernel debugging and memory manipulation.
~213 W PSU required for all XDK and XDK GB regardless of motherboard revision. This is due to the sidecar needing 3 amps on the 5-volt rail.