MacBook Pros ship with the ATI Radeon X1600 graphics cards that run at 470 MHz but owners have discovered the cards are underclocked to 310 MHz (CPU) and 278 MHz (VRAM). Apple is probably underclocking the graphics to provide better battery life and perhaps to allow the MacBook Pro to run cooler but these modification slow the graphics speed down by 34 – 41 %. What is interesting is how the owners discovered the throttling back of the GPU. They discovered while dual-booting Windows XP using Apple’s Boot Camp that the lower speeds were reported by a third party tool. These owners were able to remove the underclocking on the MacBook Pro using the same ATI tool and successfully increased the graphics speed to the ATI original specs. They also note that this does have a noticeable impact on battery life and causes the fan to run all the time. As with any modification like this you do so at your own risk.