Nunney
There is a "turbo" performance upgrade for the 9310 which will take the speed up to 450 exchanges per hour. This upgrade is just a number typed into the LMU - no hardware changes are required. This upgrade was never made available for the L5500, which is fixed at 350 exchanges per hour. The reason, one presumes, is that the library doesn't require as many service calls when running slower.
If the 9310's are moving faster than the L5500 then the 9310's are in turbo mode.
regards,
STKman.