MacBook Pro: The Thermal Paste Questionby James Duncan Davidson
Thanks to Greg Koenig for helping me during MacBook Pro surgery...
The MacBook Pro is an awesome machine. It combines the sexy aesthetics of the PowerBook with the power and speed of the Intel Core Duo processor. These performance characteristics have given us the portable Mac OS X machine we've been wanting for the last few years. The screen is bright and beautiful, and the built-in iSight camera is a nice extra touch. It's a worthy upgrade to the previous PowerBook G4 in almost every way. However, there are a few niggling problems with the first rev of the Intel-powered portable, one of which (and probably the most bothersome) is the amount of heat it produces. In fact, although we call it a laptop, it's not very usable for extended periods of time on your lap.
There are many MacBook Pro owners who have taken matters into their own hands, such as Interrupting Moss on the Something Awful website. He describes taking his laptop apart and finding an excess of thermal paste between the main chips on the logic board and the thermal pipes that transfer heat safely away. Several other people have opened up their laptops and found the same thing.
Now, what's the deal with too much thermal paste? That's a good question. In many system thermal-management designs, too much thermal paste apparently interferes with the efficient transfer of heat away from the components. Instead, you want to have just enough between a component and its heat sink to ensure solid contact and no more.
It all makes sense in theory. But you have to ask, why did Apple and their design partners, including Intel, spec so much goo in the first place? After all, they use a sophisticated heat-pipe system and have spent a lot of time optimizing every other part of the design. And these systems are obviously built with quite sophisticated equipment. Why would they ruin a great design with too much paste?
Interrupting Moss and many other folks replaced the messy stock goo with well-executed and much neater applications of high-grade thermal paste. They reported good results--so good in fact, they've tempted a large number of people to try it themselves.
Since I was willing to try anything to cut the heat being transferred into my lap from my MacBook Pro, I decided to give it a try as well. After all, I'm pretty comfortable with Mac hardware. I've cracked many a Mac, including the original Mac mini. I gave myself pretty good odds of not turning my expensive tool into a super-expensive brick. So, I sat down one evening with my friend and neighbor Greg Koenig, who is an industrial designer by trade and a MacBook Pro owner himself, to get to the bottom of things. Since we would operate on my machine, Greg's would serve as our control subject. Both MacBook Pros were updated to the latest and greatest software, including SMC Firmware Update 1.0, which updates the System Management Controller firmware.
Opening up the MacBook Pro was quite an experience. I was excited about seeing what makes it tick, as well as fearful of messing something up. It's not quite like jumping out of an airplane, but there was definitely a thrill to the entire process. After removing the battery, memory, and the top of the case (which includes the keyboard), we were greeted with the following view of the MacBook Pro's innards:
The most delicate item in this part of the process is the ribbon cable connecting the top of the case to the logic board. Next, we moved the right speaker out of the way because its cord runs across the top of the logic board:
You'll notice lots of yellow tape. That's called Kaptop tape, or more accurately, Kapton polymide film. It's a high-tech product made by DuPont that's ultra thin and designed for high-temperature environments. In addition to being used on laptops, it's also a staple of the space program.
Next, out came the fans:
The fans really caught Greg's eye. They're very high-quality in an enclosure that's made mostly out of cast magnesium. Once the fans and the SuperDrive were out, my MacBook Pro looked like this:
At this point, with a full view of all of the inspector's markings and handwriting inside the case from the factory, I was feeling the full thrill of the risky endeavor at hand. I'm not too proud to say that I really wanted a beer at this point--or maybe even something stronger. But there were questions to answer. So we pressed forward, undid all the logic board connections, unscrewed lots of screws, and lifted out the main logic board. Once the logic board was out and flipped over, this is what it all looked like:
Yes, that's what thousands of dollars of premium hardware looks like when you take it all apart. Personally, I'm amazed at just how much functionality is located in such a small package.