about innacomm w7100n,

i got some problem need help @_@

i used tplink modem 1m fixed ip download speed can up to 90kb/s , but when i changed to innacomm w7100n ,2m fixed ip, download speed down to 10~20kb/s...... i used same pc and same file test , 1m can download 90kb/s ,but 2m just 10~20kb/s , dont know why 2m more slow than 1m....
got any setting need change? hope anyone can help thank you