I heard of one guy who loaded a P133 with headloads of RAM, and got a silent HDD. On bootup, it loaded the entire OS into a RAMdrive, and ran from there. Super fast, and he wrote a script (or twenty!!!) so that any changes were written back to the HDD. Not bad - and of course with such a proc, no fan was needed.
Win 95 was his OS of choice - took a while to boot, but flew afterwards!