Firstly, why did you turn off all caches of uTorrent?
Empirically determined that it is necessary to enable them to increase the speed of the system as a whole and uTorrent including.
Set volume cache manually, empirically it was determined that the best option whether felts 200 to 300 MB, with a large number of downloads.
Also in the settings it is necessary to put allocate all files at once, not as download.
So it is better to limit the maximum number of simultaneous uploads, popular uploads is 6-10 pieces, it is possible to limit your 600 megabyte Internet link.
Helps a lot if the system is on one hard drive, and download go to another(namely the hard drive, not partition).
If you really have nothing to do I still hang uTorrent force on a separate core.