Quote:
Is BT, on any client, causing so much disk activity that it requires more extra power than I can provide?


Yes. BitTorrent on my laptop even with a 5400 drive can noticeably slow down other disk operations if the torrent is larger then memory available. I try to download DVD sized downloads overnight when I don't use the machine, things like Knoppix 5. CD sized things or smaller tend to fare much better because it's not hitting the hard drive nearly as much. BitTorrent works by receiving data in a somewhat random order causing writes to the file to go all over the place. This is due to most clients writing out the file as all 0s first to allocate space, then they go back and write real data as it comes in. And it's also going back and reading random data to serve out to other people on the network.