Awesome! Seems like the dropouts and crackles are connected to the use of my virus as Effects-unit after all. I get error-messages, saying that the virus and logic are out of sync and that i´m supposed to set the buffersize to "small" (which it is already). As soon as i stop using the sc input by setting the input-mode from "static" to "off" it is running smooth again. I upgraded to latest Beta. Doesnt change anything.
On a sidenote: I bought my virus in 2006 and still love it. I love the fact that it has become better over the years while most of my other equipment got outdated. The support always tried its best, but still..i think in all this time there were probably just 2 years where this thing worked without any workarounds or obstacles. I know its hard to make a complex device work on so many platforms under so many different configurations, but i would love to be able to just switch it on and use the shit out of it without all that hassle i´m experiencing right now...