Is it perhaps a Kingston DTSE9 G2 USB3.0 (slim metal case)?
I have one and it is dead slow writing to, and I'm not talking about it being connected to a router but directly to a computer!
Have you tested more than one USB stick?
I'm not sure what has been the fix, but I have noticed that I sometimes have to click twice on links or wait (too long) to get to the referenced page.
I was hoping this was a some bug being straightened out that resolves this behaviour.
- Fixed DNS response error issue. (from Asus changelog)
I often get the feeling I have to click twice on links to web pages to get a decent response, one click sometimes takes a long time to work.
Perhaps I'm just to much in a hurry..
I usually use the Wireless network setup method when connecting my Samsung printer to the wireless networks, it gives best control imo.
Page 99-100 in the english user guide (depending on book revision of course).