New Apple MacBook Pro CPUs throttled below base speed to prevent over-heating

Apple MacBook struggles with high-end workloads despite the Intel Core i9 CPU

Tests on the latest Apple MacBook Pros, released last week, indicate that the CPU is aggressively throttled to prevent over-heating when the laptop runs demanding workloads.

YouTuber Dave Lee, claims that the top-of-the-range MacBook Pro powered by an unlocked Intel Core i9, which costs a minimum of £2,699, struggled during rendering in the Adobe Premiere Pro video editor, for example.

The throttling kicks-in within seconds due to heat dissipation issues, claimed Lee, despite Apple's claims that the laptop's internal have been designed explicitly with cooling in mind.

The tests by Lee, better known as Dave 2D, indicate that not only does the Intel Core i9 CPU in the MacBook Pro struggle with demanding workloads, but that it has to be throttled below the standard CPU clock speed in order to prevent overheating, seriously affecting performance.

"The i9 is a very powerful CPU. When it comes to multi-core applications, this thing is a beast," said Lee. "The problem, though, is that the MacBook Pro chassis, cannot cool the i9 properly.

"When you look at renders, after a few seconds we start to see some very serious throttling," added Lee, suggesting that the output from diagnostic software had all the characteristics of a laptop that was incapable of cooling properly.

"The i9 in this laptop [the MacBook Pro] can't even maintain base frequency. Forget about ‘turbo', it can't even maintain the 2.9GHz base clock speed."

All of the CPU potential was wasted imprisoned inside the MacBook Pro chassis, he continued.

"If you have any kind of extended computational work that uses the CPU, and that's probably why you're looking at these devices in the first place, it's going to throttle. And that's unacceptable to me," said Lee. Performance bounces back when the device has been cooled for an extended period of time, he added.

As a result, benchmarks for running Adobe Premiere Pro renders on the latest MacBook Pros are many times worse than the same renders run on more conventional Windows-based PCs.

"The Adobe Premiere Pro render times are really pronounced. The MacBook will be inherently slower. That's normal because Adobe Premiere Pro isn't as well optimised for MacOS as it is for Windows, but that has nothing to do with Apple.

"The 2018 MacBook with the Core i9 is way slower than it should be. When I ran the same render with the i9 MacBook in the freezer… the difference in render time is crazy."

While a Gigabyte Aero 15X Windows laptop was able to perform the render in seven minutes and 18 seconds, the Intel Core i9 MacBook Pro achieved the same render in 39 minutes and 37 seconds - slower, even, than the 2017 Core i7 MacBook Pro (at 35 minutes and 22 seconds).

The MacBook in the freezer, meanwhile, did the same render in 27 minutes and 18 seconds.

"Power throttling and thermal throttling isn't anything new. We've seen it in MacBooks for years; we've seen it in lots of devices, including Windows devices.

"But this degree of thermal throttling is not acceptable. This is something that Apple shouldn't put out on the market… throttling like this just doesn't make sense."