This is the question that many keep asking on each passing day with some not getting the comprehensive answer that they seek for while others always get the answer, but probably decide not to take the answer as true. When we talk of a USB cable, we are talking about the wire that passes current from the charger to the device such as a mobile phone that is being charged and this basic function of a USB cable cord is something that can determine how fast or slow that the charging can be. How fast or slow that the USB can be is always dependent on the amount of current that passes through the charger to the phone and have almost little to do with the USB cable itself and that is the reason even when we have a cord that is always slow, it gets better when we use a fast charger on it. Another thing that can weaken the performance of a USB cable port is when the owner of the mobile phone is making use of it especially on the internet when the phone is charging. This can weaken the performance of the charger and make the phone charge at a very slow rate as well.