Torrents will try to use all of your bandwidth unless you set limits on them. That means you'll have more trouble sending or receiving in mIRC. It *should* still give you some speed in mIRC even if the torrents are attempting to use all of your bandwidth, but you're still better off setting limits. In some torrent clients, like utorrent, you can even set a schedule so that it limits speeds during the day when you're using the computer, but not during the night when you're sleeping.