Apple MacBook Pro Teardown Could Show a Quality Issue, or a Fluke

Two teardown experts offer an explanation of the function of thermal paste-an excess of which, in part, prompted iFixit to suggest Apple may have a quality-control issue.

When repair site iFixit performed a teardown of a new Apple MacBook Pro Feb. 25, a day after Apple released the new line-which features Intel's second-generation Core "Sandy Bridge" processors and Advanced Micro Devices Radeon graphics chips-the team was surprised to find details that raised questions about quality.

"One thing that has us a little concerned about the new models is their quality control," iFixit wrote on its site. "A stripped screw near the subwoofer enclosure and an unlocked ZIF socket for the IR sensor should not be things found inside a completely unmolested computer with an $1,800 base price."

The team also came across considerable amounts of thermal paste, prompting a "Holy thermal paste!" comment and the suggestion that only time will tell if "the gobs of thermal paste applied to the CPU and GPU will cause overheating down the road."

In the teardown images, it looks as though toothpaste had been liberally applied to some of the machine's more high-tech bits. What exactly is this stuff?

"Thermal paste is used for conducting heat from the processor to the heat sink," Miroslav Djuric, iFixit's director of technical communication, told eWEEK via e-mail. "The processor needs to have the best connection possible to the heat sink, but microscopic pockets of air-caused by very slight manufacturing differences between chips and heat sinks-prevent that connection [from being] effective (air is an insulator)."

Djuric added, citing Wikipedia, that aluminum, a common ingredient in thermal paste, is 8,000 times more efficient than air at conducting heat.

Aaron Vronko, service manager at Rapid Repair, another company that often performs teardowns, also helped fill in the picture.

"A fine layer of thermal paste enables high-powered processors in your computer to quickly and evenly offload their waste heat by filling the tiny imperfections where your processor and heat sink meet," Vronko told eWEEK in an e-mail. "Like a thin layer of glue between interlocking puzzle pieces, their thermal connection is greatly enhanced by proper application. Just like puzzle pieces though, too much thermal paste acts as a buffer pushing the processor and heat sink apart and making for a sloppy ineffective connection."

Checking out the iFixit images, Vronko agreed that there appears to be too much paste applied to the CPU and GPU, which might, taken with the stripped screw, imply that "the quality control processes ensuring uniformly correct procedures during assembly may need some review."

In the short term, it's not likely to cause any failures. However, "reduced efficiency in the cooling system typically causes the fans to run more often and at higher speeds, increasing noise and power consumption," Vronko explained. "It could also block the processors from achieving their maximum performance, slowing its use in demanding applications, and can waste battery power. Improper cooling can also be hard to diagnose in typical usage, as its effects may appear as random underperformance or quirks with video performance."

Both Vronko and Djuric noted, however, that this is just a single instance; only one notebook was taken apart.

"It's also worth noting that the cooling efficiency and design in Apple's notebooks are typically among the best, and a well-designed cooling system could essentially suffer a minor fault without noticeable impact to the user," said Vronko.

Djuric added that he couldn't recall ever seeing that much thermal paste in an Apple product before, and that "like everything else in life, the manufacturing process for electronics is not perfect."

Noting that he has a background in manufacturing engineering-which perhaps makes him more sympathetic than the average consumer to the challenges of manufacturing-Djuric pointed eWEEK to a graphic of a project triangle: a triangle with "good" at its top and "fast" and "cheap" at each bottom corner.

"Apple, just like all other design/manufacturing companies, strives for the center of that graph," said iFixit's Djuric. "But the center is near-impossible to achieve."

Apple didn't respond to a request for comment.