Well the limiting factor with the Cell (in the PS3) seems to be the in order execution pipeline that Sony/IBM used in the design. It a simplier but considerably less powerful design that the out of order execution pipelines used in most PPCs (and X86 processors - except the Atom).

If I can dig it up (or Andreas Wolf if he has the time to), figures have already been posted comparing this processor to other PPCs. Believe it or not, we're already doing pretty good in comparison with our current hardware, and the G5 will definately prove superior.

Remember, speed alone is not the only factor influencing a processor's power (think P4 vs Athlon64).

[ Edited by Jim on 2010/12/31 2:42 ]