[beagle3]

My first XT clone could would POST in less than 3 seconds if I skipped the memory test (all 640K of it), and I stayed with DOS 2 much longer than everyone else because it run almost all software at the time, and properly configured (big BUFFERS in CONFIG.SYS, for example), it would boot from floppy in 3 more.

I've recently managed to get an ubuntu server to boot as quickly (with preconfigured network interfaces and a few other things), but for years I could find the magic combination that would boot a usable system that quickly.

And I haven't seen a Windows machine that boots to usable state in less than 15 seconds (SSD, 30 seconds on magnetic hard drive) in a long time. "Usable" means you double click on something and it responds, btw - not that it shows the desktop.