Bouncing Zabaglione Bros. said:
But you can't get equivalent clocks if you have to have significantly more transisitors to support FP32 than FP24. It's probably the reason why ATI chose to design around FP24.
This is assuming that the transistors in the FP processing units are a large portion of the total number of transistors. I claim that they are not. What's more, how do you explain that the GeForce 6600 GT is, to date, the highest-clocked retail GPU available, with full support for FP32?