D&C Hardware revenue increased $401 million or 37%, due primarily to Surface revenue of $400 million. The general availability of Surface RT and Surface Pro started October 26, 2012 and February 9, 2013, respectively.
D&C Hardware gross margin decreased $242 million or 54%, due to a $643 million or 101% increase in cost of revenue, offset in part by higher revenue. D&C Hardware cost of revenue increased, primarily due to $645 million higher Surface cost of revenue. Surface product costs increased with higher volumes sold, while other costs grew as we ready inventory lines for the Surface 2 launch and the holiday sales cycle.