After some hours of trial & error finally solved..!!
The error was apparently caused by the GPU driver
(AMD HD7950,the system also acts as a game pc = dual boot on 2 SSD discs)
After deleting GPU drivers and Catalyst control center it now works like a charm.
Man, 09-z8-2 sounds really sounds more analog..!! I now hear the wood from the violin (Bach: sonatas and partitas, Isabelle Faust) and the mechanism from the fortepiano (Kristian Bezuidenhout on his last Mozart cd). I can estimate the size of a Steinway and there's more depth in the soundstage.
Very, very good job..!!
i'll change my sig and after that i'll enjoy a "cd" or 2 (maybe 3)