Comment 1 for bug 21790

to be clear, the slowness has nothing to do with upgrading; it's just that
people who used to run hoary know how fast it ran so find the difference more
noticeable.

i don't have enough hardware to be definitive, but according to the thread it
appears to affect ATA (but not SATA) drives. if i had to make a completely
unsientific wild guess, judging from the sound of the disk drive shuffling i'd
guess that the caches may not be being utilized properly.