Lag due to hdd activity in MM/HM

Often in MM/HM when mutation starts to spread and i'm the mutant, my harddisk starts to rattle very hard and i cannot move for about one second. This is of course a very unconvenient time to do a lot of disk I/O.

Don't tell me i should buy a better computer or other crap.
My harddisk is a western digital raptor 10k rpm which is faster than most regular disks.