The problem is wide spread, you can find the same thing for about any mainboard that has USB3 onboard, also with PCIe to USB3 cards, and for about any external USB3 device there is.
Personally I have 9 external HDDs, different sizes, different boxes.
I have 3 PC´s with different mainboards, USB3 onboard or PCIe card, or even both.
Obviously I have 9 cables and 9 power supplies as well.
The problem persists with ALL of them in any combination of PC, drive, cable, etc.
I have all all the latest firmware, BIOS, drivers, for all 3 systems, but it makes no difference at all, whether I use the old or the new ones, the problem remains the same.
Furthermore, the problem appears on random, sometimes the drive drops out after copying less than 1GB, next time I can copy 150GB without problems.
You may imagine, within such a variety of hardware, there is virtually no chance of hardware defect, and since I tried all the latest drivers as well, there is no chance for a software problem either.
That´s how I got to a new idea, even though it seems to be a topic from ancient history, an IRQ conflict.
It would lead a bit too far to explain here about IRQ´s, neither can I give you details of how to solve them, I´m sure Google will find it for you.
Fact is, IFFFF you manage through BIOS and system settings to set your USB3 controller to an IRQ that isn´t shared with anything else, there are no dropouts anymore.