I just tried Firetip (java application) while using IB Gateway,and went to Task Manager to see memory usage after a while they were running. Both usages were quite stable at arount 100MB. But while the Gateway is a TCP relay with no graphic interface, Firetip is a complete trading application now running 1 graph window, 3 DOM windows, 1 Account detail window and 1 trading matrix window, inside the main application window. IB, doesn't make you think?