Telnet/SSH into the router when downloading a large file with QoS enabled, enter the command top, look at CPU load (it will probably be at or above 1). QoS is CPU-intensive, with rising load as the bandwidth increases. Disabling all non-essential processes may be helpful, such as PnP, USB, ethernet port states, ip traffic and bandwidth monitor, web monitor, etc. Not sure if you can overclock an E2000. You can also compile Tomato with CPU optimization flags (-march=kwhatever -o2) As for QoS settings, disable (don't delete yet) any L7 filters. If your CPU load is less than 1, let us know and we'll rethink the situation.