Trying to speed up downloads

[Meffy]

It's not really a speed problem but Im unsure where to post this.Im using a slow hard drive...5400RPM and its a laptop one.Im wondering if its possible to improve my download speed by modifying the diskcache settings(Pity not much infomation is given about these in the speed guide).Im using XP2 and a 6.5mbit connection and the defaults in utorrent.

Thanks!

EDIT:When im burning DVDs and etc,i noticed my dl/ul drops and goes back to normal after the dvd is burnt..can this be minimized by modifying my settings?