I am using a M5A88-V EVO MB and recently tried to use an external hard drive that is USB 3.0 enabled but had problems with 2 different hard drives. I bought a Seagate brand hard drive and a Western Digital MyBook or something like that. Anyway, the problem with the first one was similar to the problem with the second one. However, the first hard drive would connect up to the computer and the autoplay would come up but after about 3 seconds it would disconnect and not show up again unless I unplugged then re-plugged the USB back in. It would still do the same thing though unless I hooked it up to a regular USB 2.0 port. It would work just fine then.
The western digital hard drive had a similar problem, but would stay connected until I tried to transfer a large amount of data. If I transferred just one document it was fine in the 3.0 port but anything that required a progress bar would cause the hard drive to disconnect spontaneously and then just as quickly reconnect. It would beep that it was disconnected and the transfer would stop, then it would indicate through sounds that it was connected again and I could sometimes hit try again but sometimes could not. Just like the other hard drive, if I plugged into a 2.0 port it would work just fine.
I have all the proper drivers, updated, everything is in order except for the USB 3.0. I do not have any other devices to see if it is device specific or if it is just a problem with the ports. Also, I have disconnected multiple fans and turned others down to see if it was a power problem but it made no difference. I even plugged the power for the hard drive directly into the wall outlet just in case it was not getting enough power. If anyone has had experience with this problem, please help. I am a certified technician and will understand just about any explanation you may have. My complete system specs can be seen through the "My System Specs" feature this forum provides.