Actually, though this is going off topic, that isn't necessarily true. A PC CPU has to run a clunky OS and a wide variety of applications. It needs legacy support and a very developer-friendly design that'll run all the apps coming from a widely varying pool of programming talent. A console CPU is only going to run optimized code that's passed by the hardware companies and so the can forgo the niceties and legacy support and go for outright targetted parformance. As long as a PC CPU has to run old and flakey code (the sort I write!) hardware is going to be constricted from super-turbo performance.
As a comparison, how long did it take for PCs to catch up with NES 2D capabilities? And how's about SNES 2D abilities? AFAIK generally the consoles were better at games because the hardware was targetted at games. There's no reason for this to change. The only real difference with modern PC's versus consoles is PC's by their nature spearheaded 3D graphics, and a large industry of 3D accelerators has cropped up. But consoles can still aim to be custom gaming-monsters in the CPU department whereas PC CPU's will always have the ball-and-chain of legacy support holding back their key performance. If the high vector-streaming capabilities of XeCPU and Cell really do make a big difference, a standard PC isn't going to have a similar CPU functionality for a long time. Unless a standard in vector-processor addons can be developed, there's certainly potential for the consoles to remain ahead in the processing department.