latency of opening mail.app in macOS Tahoe vs Monterey
Tested on my base M2 MacBook Air(2022) with 8589934592 bytes of ram and 20000000000 transistors. All other applications are closed (quit); except Finder.app, Terminal.app and screen-recorder process. Measurement by recording a 60fps video and counting the clip duration frames later in DaVinci Resolve.
macOS Tahoe 26.1
$open /System/Applications/Mail.app
+ 0 frames + 0ms push enter + 95 frames +1583ms window appears + 90 frames +1500ms inbox list gets drawn + 72 frames +1200ms most recent email text gets drawn =257 frames=4283ms (phew!)
Here is the same test but mail.app is already open (window closed):
+ 0 frames + 0ms push enter +24 frames +400ms window appears +10 frames +167ms inbox list gets drawn +16 frames +267ms most recent email text gets drawn =50 frames=833ms (phew!)
macOS Monterey 12.7.6
details on downgrading to macOS Monterey
After a few weeks of using Tahoe, I downgraded to macOS Sonoma (fresh install).
It was much better than Tahoe.
I used it for a few months.
However, I was still experiencing bad latencies when opening applications or navigating in Finder or System Settings etc.
After a few months, I downgraded to macOS Monterey from Sonoma (yes you heard that right, monterey in April 2026!).
Unfortunately I haven't tested Sonoma latencies. My intuition is, Sonoma is faster than Tahoe and slower than Monterey.
Why Monterey?
It was the newest version that had the chance of being fast and still getting served on Apple's servers.
I first fell into the trap of using softwareupdate command to get the Monterey pkg.
The softwareupdate wasted my 12GB bandwidth by downloading Monterey and recklessly auto-deleting the InstallAssistant.pkg because of "not meeting Gatekeeper policy".
Unfortunately, macOS is not 90 kilobytes. It is (as Arthur Whitney puts it) a "telephone-number sized" operating system, more specific: 12409187001 bytes.
This "sucatalog" file has an index of macOS versions.
I manually re-downloaded the file InstallAssistant.pkg with the cd ~/Downloads;curl -LOC - https://swcdn.apple.com/content/downloads/24/16/062-40406-A_LQ4WW26M04/j7bl9ygay5prezturwh72ai10fvseh2uhw/InstallAssistant.pkg.
Double clicking on it created /Applications/Install Monterey.app folder.
Then I prepared my 32GB flash drive with sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/USB and installed it from Recovery.
And I got my data back etc.
$open /System/Applications/Mail.app
+ 0 frames + 0ms push enter +44 frames + 733ms window appears +15 frames + 250ms inbox list gets drawn +33 frames + 550ms most recent email text gets drawn =92 frames=1533ms (phew!)
Here is the same test but mail.app is already open (window closed):
+ 0 frames + 0ms push enter +10 frames +166ms window appears + 6 frames +100ms inbox list gets drawn +15 frames +250ms most recent email text gets drawn =31 frames=516ms (phew!)