1) if you have such fast connection, you have to set buffer to 512kB or 1MB
(I have 100Mbps too and it really uploads 11MB/s)
2) choose the right server - not all servers allow you to upload such fast! eg. hotfile max. is 500kB per connection. I don't know what server do you use, but it might be server limitatioin. You can still use more connections.
3) speed limiter is default off, I don't suppose my program limits uploads when you don't set it
provide me more informations