Fast charges my Galaxy S8+ just fine. I think the people having issues must have bad cables (or received a damaged device, it happens).You need a thicker gauge wire in order to fast charge.Trimmed comment from another Amazoner: ""Micro USB cables use two wires, one for data and one for power. Most are 28 gauge for data and 28 gauge for power(28/28). While 28 is fine for data, 28 for power limits the amount of power that can be transmitted to the device you are charging. Hence with 28/28 you will have slow charging. The problem with most cables is that there is basically no way to tell whether they are 28/28 cable or a 28/24 (the lower gauge number is thicker wire). Some better cables are 28/24 or even better. Newer cables can be found that are 28/22 hence when used with an adapter plug that is rated at 2 amp hours the device will charge faster if the device being charged is capable of accepting 2amp hours.""