It depends. For instance, for the PS3, while it has a weaker GPU, most of the programming is done at a much lower level (Assembly + low level machine API's) then you would see on a PC platform, hence why consoles in general can run the same games depsite have weaker all around hardware. Likewise, consoles have much less running in the background.
As such, its apples to oranges. From a pure processing power standpoint, the Cell would win, and win big. But that assumes it is used to capacity, which itself is hard to do.