Two GPUs in MacBook Pro 15″ and 17″ – manual switching
I have noticed that a significant number of people working with video, motion design, visuals, etc. don´t know that their computer has two graphics cards or GPUs – Graphics Processing Unit. One has a lot of horsepower and dedicated video-RAM to handle 3D-graphics, HD-editing, gaming and such, which includes live visuals. But using this one also makes the internal fans to run about 50-150% faster, since the lap top gets pretty hot, and the battery is drained much faster.
The other GPU is not as effective in handling demanding graphics, but it is much more energy efficient which makes the battery last longer and it keeps your laptop cooler. Even the total life span of the computer can increase, since the internal pieces are not exposed to the same amount of heat. (Actually my MBP 17″ tops about 100+ celsius degrees when rendering for a long time.) This GPU is more than enough for office softwares, web browsing, and such. It has no dedicated video-RAM, but uses the standard RAM in your computer. A solution which is called integrated graphics.
This is true for all the early unibody Macbook Pros with 15″ or 17″ screens. Thankfully the later models have an intelligent way of switching between the to GPUs without any effort from the user, but with the earlier ones (early 2009 and on) you need to switch manually. It is easy and fast and the instruction is comprised in the the screen shots above. You will have to log out after clicking “Higher performance”, but just log back in and you are ready to go crazy on a new level!
Details here: http://www.apple.com/macbookpro/specs-compare.html