hi again.
"Out of memory" problems almost disappeared when i upgraded from very old router to new one. So it may have something to do with data transmission/memory management. I still get "out of memory" error but only like once a week, and never with youtube, but after switching from youtube to smart share. It was impossible to watch for example a 8GB full hd movie or a short clip - now it is almost OK, as i said. Still not perfect, but enjoyable