Before this I am using UTorrent 1.8.5 and download speed is great. Max out my 2Mbps DSL connection (around 200kbps++). So when new upgrade available, I happily upgrade to new version. Little did I know what it come with…
The download speed is very slow. Rarely reach even 100kbps. Most of the time around 50kbps only. I am tired of waiting… I try to download torrent with more seed. But it still wont go up to the old speed. Now I start to Googling around.
I found the tips in UTorrent own forum.
Go to your Preferences (Options -> Preferences or Ctrl + P)
Then change the value in Advanced.
bt.transp_disposition from the default 31 (default value on mine) to 5 (as suggested by one of the forumer).
After that, the speed of download increase to a bit around 150kbps… But still drop back to 50kbps sometimes. So this one does not solve the problem totally.
Then one more forumer suggested that change the value of net.calc_overhead. From True to False.
The new version of UTorrent is somehow limit the download speed to the rate of limited upload rate. So if your upload rate is 5kbps like what I said, you’ll get 50kbps download speed.
This setting will disable that options. So you will get your full download speed 
Nice!
Or you can just increase the upload speed limit to get more download speed. Or you can always downgrade to older version of UTorrent.