I know a lot of you, me included until recently, have been unable to overclock our C2D MacBook Pros because ATITools wasn't recognising the X1600s current speeds and was crashing whenever it was clocked at above like... 10 10. Well, I managed to get overclocking on my C2D MBP by updating to the recent update of Omega drivers and using ATI Tray Tools which fully recognises all the X1600s current settings and will allow you to clock up to some pretty amazing speeds. My old CD iMac could hit about 400 450, up from it's default speeds of 300 310. That was pretty nice, but anything above that would cause severe spaz chucking. But hoo hoo, boy oh boy, can my C2D MBP whip that. I'm at 445 520 right now, and Prey, maxed out (although at one res lower than native, because I actually find that this causes a natural antialiasing that compensates for the minor decrease in detail) runs quite literally butter smooth, whereas without overclocking I had to disable some of the higher end features and even then would achieve slightly stuttery fps. It seems these MBPs aren't as comfortable overclocking the GPU Mhz - I can't go above 445 without it having a stroke - but it's able to seriously push the memory speed. I think I could probably get away with 550, maybe 570... who knows even 600. But for now I'm sticking with the safe bet of 445 520. It's like a new card!