My friend had a 486 (We only had a 386), but it would play doom really well.
However, the first step of any gaming session was to reboot the machine with the boot floppy in, which had the right boot settings for gaming performance.
Starting with DOS 6.0 (which came out before DOOM), there was an option to create a menu where you could choose different CONFIG.SYS (and AUTOEXEC.BAT via a variable) options. No need to edit it every time or use a floppy just to get different settings![0]
However, the first step of any gaming session was to reboot the machine with the boot floppy in, which had the right boot settings for gaming performance.