That's true, NT was much more resource demanding but there were other mitigating factors too. Drivers were either inefficient and or badly written, the video driver imposed inflexible rules on software's access to the underlying hardware and its plug-and-play feature was brain-dead from the outset. Most of these problems weren't fixed until Windows 2000.

Incidentally, I've always thought W2K—taken all round—as the best version of Windows, it's the version with minimal dross and useless stuff and MS hadn't got into spying on users by that stage.