having a windows explorer window open with lots of files with meta-data seems to cause the cpu to rapidly use up 100% of cpu. its because of the heavy harddisk reading.

downloading large files while doing this only helps to increase the harddrive activity because of large chunks of data being written and re-checked by limewire.

my suggestion is to defrag your harddrive after downloading a few rather large files. after downloading lots of small files, a defrag isnt necisarry, but may help improve performance. my extra advice here is to have a defrag scheduled atleast once a week.