It shouldn't make a difference unless the power cord that you're currently using isn't heavy duty enough. If those amps are capable of drawing 20A from the wall, then you'd better have a 12ga or 10ga power cord on them. Similarly, you should be running a 10ga or 8ga line to that outlet to minimize resistive loss.
However, if you've got proper gauges of cables, then no, a power cable will not make a difference, and it certianly won't make a miraculous improvement.
