Appleis Intel Core Duo replacement for the PowerBook G4, the MacBook Pro, sports an ATI Mobility Radeon X1600 video card. According to ATI, it operates at 470MHz. On the MacBook Pro (MBP), however, it runs at 310MHz - about 34 percent slower.
Odds are Apple chose to under-clock the MBP video card to conserve battery power. With the video processor running at full speed, itis likely to shave about 30 minutes off of the battery run time.
According to Moneycontrol Tech Blog, the information surfaced after users started installing Boot Camp on their MBP systems so that they could run Windows XP. While booted in Windows, they noticed that the video card was running at 310MHz, and the video memory had been slowed down about 40 percent to 278MHz.
It appears that the pull back on speed isnit imposed at the hardware level, so some MBP owners have taken to resetting the video processor speed themselves. A post at Hardmac discusses doing just that. Using ATI Tools beta 0.25 R14 in Windows, you can push the X1600is clock speed back up to its maximum level, and potentially see dramatic improvements in graphics rendering when you are booted in Mac OS X or Windows XP.
The problem with modifying the video card clock speed is that it runs hotter and uses substantially more electricity. Some users are reporting that their laptop fans turn on almost immediately, and run at speeds higher than they have experienced before.
So far, the people that seem most interested in improving their MBPis video performance, and potentially voiding their warranty, are gamers. Games typically push video cards harder than business-related applications, and dropped frames in games like Quake or Unreal Tournament can give your opponents the advantage.
On the surface, changing the clock speed sounds like a great idea: better video performance means better quality in video games and other graphics-intensive applications. The problem is that Apple chose to under-clock the MBPis video for a reason. Increasing the speed could potentially cause heat dissipation problems, power usage issues, and ultimately lead to hardware damage that Apple wonit repair under warranty.
So why exactly did Apple choose to reduce the Mac Book Prois video speed? Since Apple wasnit available for comment, we can only speculate, but the idea that it results in better battery life and reduced heat output seems pretty reasonable. Even with its hobbled video, however, most reports say the MacBook Pro performs very well.