So how is this better than the Mobility Radeon 9700? Take a look at this
http://graphics.tomshardware.com/graphic/20050524/vga_charts-02.html
The 915G is bottom of the list for PCI-express graphics (yes I know it's not the 915GMS but if it's even twice as fast as the 915G, it moves off the bottom, to second last)
The PB supports dual DVI without a dongle.
Potential? Yes, but where's the real world gain? In the real world, the ATI x700 shows little improvement over the ATI 9700. Any there is is not worth getting worked up about.
I'm still waiting for an explanation of why PCI-express would be an advantage in a laptop, considering you can't actually upgrade to a different card. In a desktop, it's different.