IIRC, Win2000 would wait for most/all services to complete startup before showing the login UI. XP would allow login as soon as enough of the system was started to support it. The tradeoff is that you might have slow performance from HDD thrashing while everything else finishes starting up.

It's been 20+ years so it's possible I had it wrong then, or remember it wrong now.

No, that's pretty accurate as I recall. Windows 2000 took a bit, but when it was up, it was up. Windows XP would pop you into what appeared to be a functional desktop quickly, but it was still loading in the background, and some things just sort of sat there for awhile. Win2K was much more predictable. When I wasn't on a Mac during my consultant days, it was on Windows 2000, because it was much more stable than the 98 clients.

> The tradeoff is that you might have slow performance from HDD thrashing while everything else finishes starting up.

You would often get audio buffer underuns on the startup sound, if enabled, especially if you had auto login.

XP started drivers and services in parallel. 2000 started them serially. That was the difference in startup speed.

I no longer remember when we could configure services as delay loading, most likely around XP timeframe.

Windows 2000 was the first release of NT5. That's what made it 2000.

Windows ME on the other hand...