Marco Arment:

When Turbo Boost is enabled, the fans annoyingly spin up every time the system is under a heavy sustained load. Disable it, and it’s almost impossible to get them to be audible.

Marco is testing this on a 16-inch MacBook Pro with a Core i9 CPU. I have been using a Core i7 extensively for two weeks and have found that it takes longer to spin up that some of the i9s that I’ve heard of. As an example, after fully loading the CPU and GPU with a longer (30 minute), intensive task, it took 30-40 seconds before that fans spun up past 3000 rpm (that’s around the time they start to be irritating) and got up to 4800 rpm after 90 seconds (that’s around the region I cannot tolerate them any more). The case itself doesn’t seem to heat up as much as in the i9 too. So basically, for short bursts of power, lasting up to 30 seconds, the i7 doesn’t seem to spin up the fans noticeably.

Either way, I have been using Turbo Boost Switcher Pro for years and can heartily recommend it. An Apple-sanctioned Low Power Mode would be even better.