The MacBook Pro 17" X1600 is faster!

While the Radeon X1600 of a MacBook pro 15" seems to be set by default at 300 MHz for the GPU and 300 for memory, it seems that on the 17" model, the first reaches 400 MHz and the second 450. Those values are close to the specifications of ATI for this video card.
It would seem that the bigger battery and perhaps a better cooling system in the 17" allowed Apple to make no compromise at this level.