@Sunshine any further ideas (except giving it back and buying from another vendor ;-))?

@Sunshine The wired speed is always fast ~100Mbps. In the mentioned software it is only possible to disable power safe mode on the none wifi device the other does not offer this option.

@Sunshine 5Ghz is slow (~2Mbps) too now (this afternoon it was fast ~80Mbps). The link speed of the windows device is shown as 866,7MBit/s. I read something about a power save bug in some wifi...

When connected via ethernet cable to the tl-wpa8631p 4.0 I have ~40Mbps download and upload speed. Via a wifi connection the upload speed is the same but download is ~3Mps. The wifi is using 40Mhz on...