@jacad:
I'm not sure what is happening here! I have two locations, where I use MorphOS - one with cableconnection and the other one with SIMM-Card-Router.
I am now at cableconnection and it seems to be OK (G5/2,3GHz)
The problem was with SIMM-Router on a G5/2,0GHz. Normaly speed of Simm-connection is more than enough (I watched YT 720p without any artefact or else in the past).
Yesterday every YT-video crashed after a few secons (no changeing any prefs). That means: Not Wayfarer itself crashes, but the movie shows only (really wild) artefacts on the screen (like brocken decoding). Audio was OK.

Im back at that location next weekend and can test further - perhaps it's a router-problem (?)...