Almost any copier will use enhancements (fast loaders/savers) or direct track reading/writing. Unfortunately, the 1541-III does not support any type of such software:
"Because the circuit is based on a PIC microcontroller and not a fancy FPGA or 65xx processor it will never act 100% the same as a 1541. This is the main reason why fastloaders will not work as on a real 1541."
Let's face it, the 1541-III is quite old and obsolete, there's better things around, like SD2IEC, which is very affordable, more compatible and brings a bunch of software with it.