Is it true that using torrent clients makes computer...

[csp-expert]

...very slow? What's the exact reason?

[el_smitz]

Torrent Clients can use a lot of memory due to the huge amount of work they have to do - ie.: re-assembling the huge files that they are downloading, and checking them for errors.Try using YABC or mewTorrent, these are very small and dont use a lot of memory.