USB 3.0 on the Asus X750J laptop seems to work in 2.0 mode. What to do?

Question

ASUS

Hello. I've been fighting for the second week, I don't understand what the problem is. There are two USB 3.0 ports, they used to work fine, they wrote data to a USB flash drive at speeds up to 30 MB / s (28-30 MB / s). Literally two weeks ago, problems began and the speed dropped to 7 MB / s.
The flash drive works correctly, I checked it on a computer and another laptop with 3.0 ports.
Tried reinstalling drivers, nothing helps. Perhaps you can help me find a solution to this problem.
Thank you.
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With uv. Vladimir