Windows NT on 600MHz machine opens apps instantly. What happened?

Only Windows has this issue. There's nothing about my Mac or my Chromebook that is anything less than immediate. You can quibble about whether the compositor introducing an extra frame of latency was worth the tradeoff, but that is on the margins.

The Mac is no better, in my experience. I just timed how long it takes to open the Calculator app – the simplest app I could think of – on my 2019 MacBook Pro, and the window appears 600ms after clicking on the dock icon. I would not call that immediate, and it only gets worse when you try more complex applications, especially those written in Electron.

VSCode is ~1s.

Terminal ~300ms.

iTerm ~400ms.

Calculator ~300ms.

Firefox ~1s.

Textedit ~200ms.

Slack ~1s to appear, ~5s to load.

Sequel Ace ~800ms.

Fork ~500ms.

All my subjective experience, but it's basically instant in experience. I think it also helps that it doesn't show fade in/out animations, which LOOK sluggish to me.

M1 MacBook Pro from 2020...

Code comes from the same shop that writes Windows. However, I would compare that with older software of similar purpose and capability. How long does it take to launch Visual Studio '97? According to some youtube screen recordings, VS '97 needs over a minute to draw a window even with a hot file cache, which is consistent with my memory.

On my M1 MBA, I just tried measuring opening Calculator using QuickTime screen recording, and then the "trim" function to determine 10 ms precision. It takes 260 ms. Definitely fast enough for me.