Linux

I think both the Windows NT Kernel and the Linux Kernel are solid speedy parts of the OS. The main bloat is what's on top.

Windows seems to have progressively more bloated phases. Newer stock Windows programs are built from much heavier components.

1. There's the Win32 phase, which is super fast and lightweight. Few programs are still alive using this phase, WordPad (RIP) is one of them.

2. Then there's the broad Win64 phase, comprised of mostly Win Vista/7/8/10 parts. Word, Excel, and the old Outlook are examples of these programs. Slow upon their inception, they have become considerably faster due to better hardware, but still aren't very snappy.

3. And finally there's the new phase, Windows 11. Horribly bloated and laughably slow when pushed beyond the absolute basics. Examples include File Explorer, Notepad, Teams, and the new Outlook. Notepad is mostly fine, but even File Explorer takes multiple seconds to load basic things on midrange hardware. We all know how bad Teams is, and the new Outlook takes 30 seconds to launch and open an email even on high end hardware.

Much of the modern bloat comes from this latest phase, but somehow other parts of the system have seriously bloated as well, like all of the disk processes on startup and even the Windowing system, which used to be near instant on crappy hardware back in the Win2000 era, now takes up to a second on modern midrange hardware on 11.

Linux has fared better against the onset of bloat than Windows, which is the main reason why it feels much snappier and uses less memory. Despite this, you can still see Linux getting significantly heavier over the years, from the super lightweight Trinity Desktop to what we have now. But, web browsers powering many greedy tabs can easily out-bloat GNOME, to the point where Linux only feels slightly faster than Windows because everything is in a browser.