This article describes details about implementation of Commodore 64 emulator written in C#. The performances are not that great, because of several reasons, like cycle-based and real drive emulation as well as the way some things are implemented in source code. I re-implemented the emulator in C++ for other purposes and the implementation yielded a great increase of performance. In the wake of these results I abandoned the C# implementation. Since it would be a waste time and effort not to use the code available in some way, I decide to write an article about the subject.