A pentium (or 486 in the worst case) is required.
Official mirrors are:
quake.best.com/pub/idsoftware
ftp.netural.com/pub/idsoftware
ftp.cdrom.com/pub/idgames/idstuff
uss-hood.starfleet.com/pub/idstuff
ftp.islandnet.com/mirrors/idsoftware
ftp.stomped.com/idstuff
ftp.netvision.be/pub/idstuff
ftp.nijenrode.nl/pub/idstuff
ftp.flashnet.it/pub/ftp.idsoftware.com
hyperactive.com.au/pub/games/idstuff
[actually, it wasn't here, last time I looked]
garfield.sch.bme.hu/pub/idstuff
ftp.gamesdomain.co.uk/pub/idsoftware
rajah.trin.cam.ac.uk/pub/idstuff
src.doc.ic.ac.uk/packages/idgames/idstuff
ftp.passagen.se/pub/idstuff
ftp.connectnet.com/pub/idstuff
linux.mit.edu/pub/games/quake
ftp.LAME.org/pub/quake
isengard.stanford.edu/pub/quake
turing.vironix.co.za/pub/quake
enjoy,
-- I.S.