Before 1 test run, the hard drive was examined whether the latest WD firmware was installed - this was true.
Then I divided the hard disk into 4 partitions because more are not recognized at the Fritz box.
There are several folders with different files (MP4, FLV soie MSI and zip files) copied to the hard disk.
Result: just 45MB / sec. has been achieved, which is far too little on USB3 port.
Correspondingly similar bad the readings, thus copying the hard disk back to the computer.
A for comparison Transcend Store Jet scored values between 60 and 70 MB / sec, also this model is better protected by a silicone-damped chassis to shocks.
WD-plate went back to Amazon.