The latest revision of NextGen Controllers User Manual (v.1.3, updated September 1, 2013), section 15, subsection "Print Command Restrictions" states that the motor controller can sustain the output bandwidth of 32 characters per 1ms. How can this speed be feasible at 115200 baudrate?
32chars per 1ms = 32,000chars per 1 sec = 320,000 bauds (8bit + 1 start bit + 1 stop bit per character) per 1sec.
320000 is almost three times more than 115200.