Older versions of macOS run much smoother, even when just idling !

My 2019 macbook pro 15 felt a bit sluggish with macOS 12.6.3 Monterey, and had overheating problems whenever it did something a bit more complex then browsing the internet. (Sometimes not even that complex, a single connected external hard drive was often enough to send it spinning!)

And this was with the top of the line, at the time, octa-core Intel i9 with 16 virtual cores.

To give some context, in the most ideal possible scenario, idle CPU usage as reported by Activity Monitor hovered around 3% on a fresh install without anything going on, no peripherals, no connected accounts, no bluetooth devices, etc., just idling on the desktop doing nothing.

That figure easily doubled in a more realistic idle scenario. Such as after signing in to all the iCloud services and connecting to Wifi, ‘Hey Siri’, and opening a Finder window.

It typically fluctuated between 4%-7% depending on its mood.

So after getting fed up one too many times I decided to try downgrading to macOS 10.14 Mojave today, the OS that came with the macbook at launch, and guess what happened?

Yes, the numbers your seeing above are the real world performance numbers when idle with all the things you would expect, ‘Hey Siri’ active, WiFi connected, iCloud logged in, etc. The numbers are not photoshopped or altered in any way.

1.2% CPU usage!

A fraction of the consumption with software just 3 years older, (and which still has 90% of the features of the latest and greatest).

To be honest, I wasn’t expecting such a huge difference without even doing anything yet on the computer.

And there are no annoying overheating spurts either, not during idle nor regular usage such as web browsing, word processing, connecting external hard drives, etc…

It also feels perceptually so much smoother navigating around, without noticeable jitter or lag at all. Even with dozens of windows open.

So much so that I’d dare say it feels faster then the latest and greatest M2 macbook pros running the latest version of macOS Ventura.

As an aside this perceptual difference would never be captured in a synthetic benchmark like Geekbench, since raw horsepower matters the most in those. Yet I think this is a huge, perhaps primary, component for end-user satisfaction.

So it really surprises me that Apple has paid much less attention to it in recent years. Perhaps the ARM transition required some sacrifices along the way, or some other dynamics prevented focusing on smoothness of experience.

For a real world moderate duty scenario, a typical workload with the following going on:

  1. Time machine backup
  2. iTunes running and playing music on an external display
  3. Terminal window open
  4. Dictionary open
  5. Keychain open
  6. Mail open
  7. Notes open
  8. Dictation on
  9. Bluetooth on
  10. Wifi on
  11. Chrome open with a dozen tabs
  12. Screen shot utility active

Yields CPU usage that does not exceed 8% usually, hovering between 5% to 8% as you can see:

Which is still incredible considering that the fans are totally silent and the keyboard is still comfortable to the touch. The exact same scenario on the same computer with Monterey would have meant occasional overheating.

In short, if you have an older mac lying around that feels sluggish or overheating-prone on current macOS software, I recommend giving a downgrade a try to see if you might be pleasantly surprised too.