Every ~10 s my ping was as high as 2000ms. (ping www.google.com -t).
Online gaming was horrible due to enourmous lag..
By removing Magix Connect problem disappeared.
Windows 10 64bit, Wlan.
Why this occured I have no idea.
Only clue to solve this were that Magix connect being quite active in Task Manager without giving any processor load % anyway.
Other one was that this add-on was installed two day ago.