I don't think the problem is caused by SmartFTP. There are many layers between SmartFTP and the server which may influence the transfer speed. Also in the 10 years we have been developing SmartFTP we never experienced a single case where SmartFTP would be slower than any other FTP clients.
I must admit I'm disappointed in your response. The issues I describe are consistent on upload. Do you have an suggestions or settings I can use to speed up the upload? Why if I stop one thread don't I get a single thread at 180Kb/s? Logically by your prior example I should correct. Like I said it limits with out question at or around 90k. I'm running vista, I work in a data center with a 10Gb fiber connection so I really want to work as fast as other programs are capable. Looking forward to your thoughts and suggestions.