Although it uses the same basic chip (GF100) and architecture as the desktop GTX 480, its mobile variant will have the core clocked at 425MHz, 352 stream processors clocked at 850MHz, and a GDDR5 frame buffer running at 1,200MHz on a 256-bit bus. No mention of power consumption was made. Right now, the only PC manufacturer confirmed to be working on a GTX 480M systems is Clevo, but other companies should follow with their own announcements shortly.
On a related note, it is being rumored that Nvidia's cheapest DirectX 11 graphics processor on the desktop is being axed after only two months on the market. According to Taiwanese sources speaking to Kitguru, the graphics firm has stopped taking orders for the GeForce GTX 470, perhaps to make way for a new GeForce GTX 465 model.