MacBook Pro laptops
Photo: Apple

A popular YouTuber’s recent review of the new MacBook Pro has sparked a wider discussion of a process called “thermal throttling” that many consumers with high-end laptops could run across.

The review, posted July 17 by Dave Lee (“Dave2D”), appears to show a just-introduced MacBook Pro with an Intel Core i9 processor performing more slowly than a MacBook Pro with a slightly less advanced Intel Core i7 processor. For instance, it took more than 4 minutes longer than the i7 model did to render a 4K video in Adobe Premiere Pro.

Both the i7 and i9 processors are high-performance chips compared with the processors in most consumers’ laptops.

More on Laptops

Lee attributed the decreased performance to a process called thermal throttling. When computer processors, or CPUs, approach a temperature so high it could damage the chip, the processor slows in order to cool down.

Consumer Reports hasn’t repeated Lee’s experiment, but CR testers say the result isn’t that surprising—and the issue doesn’t apply only to MacBooks.

“Most processors have had this capability built in for years,” says Richard Fisco, an electronics testing program leader at Consumer Reports. “I would rather have the system throttle and take a lot longer to do things than just let itself get fried.”  

Lee couldn’t immediately be reached to discuss his findings. Apple declined to comment.

Laptops vs. Desktops

Desktop computers and hulking gaming laptops don’t resort to thermal throttling as often because they have more built-in cooling equipment, including large fans and pipes that conduct heat away from the processor.

Manufacturers have been competing to create thinner and lighter laptops, and these sleek machines don’t have as much room for these cooling mechanisms.

“A laptop is the worst environment you can think of for a processor,” Fisco says. “There’s just not a lot of space, so you can’t cool it as efficiently.” In another recent video, Lee said he found thermal throttling in the new Dell XPS 15, which also uses an Intel Core i9 processor.

When Lee placed the MacBook Pro with the i9 in the freezer, he said on YouTube, the laptop was able to render the video in 12 fewer minutes.  

What Can You Do?

Well, you could do all your video editing in a walk-in meat locker. But short of that, you can’t defeat thermal throttling. And you wouldn’t want to, unless you’re looking forward to using your laptop as an expensive paperweight.

However, if you’re computer shopping, it’s a good idea to keep thermal throttling in mind.

Given that laptops are more susceptible to thermal throttling than desktops, if you absolutely need bleeding-fast speed—perhaps you’re a programmer who regularly compiles large applications or someone who edits huge amounts of high-resolution video—a high-end desktop may be a better bet than a souped-up laptop.

High-end gaming laptops may also be worth considering.

And if you’re an everyday consumer whose most computationally heavy task consists of applying the occasional Photoshop filter, you can largely sidestep this problem by choosing a slightly slower processor in the first place, such as an i7 or i5.

Sure, these may not be as fast as the i9 in the MacBook Pro, but you’re unlikely to notice any difference between the processors when doing simple things such as switching between Facebook and Gmail tabs in Chrome or watching baseball highlights on YouTube.

“An i5 is generally more than enough, even for spreadsheets—unless you’re doing crazy calculations,” says Maria Rerecich, who manages all electronics testing at Consumer Reports. “Where you need that higher power is when you’re doing rendering and that kind of intensive graphics work.”

And if you can get by with an i5 processor, you’ll save money on the laptop, too.