Yes, and you will note I said "slightly faster CPU and GPU". The point is that the whole device is much more resource constrained, as what needs to be done with the CPU and GPU on the original iPad is more than on the iPhone 3GS, but the CPU and GPU are not faster enough to create the same effective performance.
Yes, raw performance may be better on the original iPad. But raw performance is irrelevant if you can't get the same effective performance for the user.
