Popular Mechanics:

Spend a few tens of thousands on optional upgrades, and the new Mac Pro becomes a list of superlative performance specs. But those numbers also come with a lot of heat. That means Apple engineers have to find creative ways to exploit the laws of thermodynamics.

“Years ago, we started redistributing the blades,” Chris Ligtenberg, Senior Director of Product Design says. “They’re still dynamically balanced, but they’re actually randomized in terms of their BPF [blade pass frequency]. So you don’t get huge harmonics that tend to be super annoying.”

Really interesting technical discussion about the innards of the Mac Pro.