HyperSID is a free midi controller VST plugin developed by HyperSynth. Compatible OS(s): Windows.
HyperSID is a realtime MIDI synth editor that allows you full control of every sound shaping parameter found on a HyperSID hardware unit. This hardware unit is based on the old C64 synthesizer Chip (SID) and It is a kind of “DIY” project. Real time integration between software and hardware makes HyperSID act like the other VST instruments in your host application. Because its sounds are fully generated by the hardware unit the VSTi Software has a very low CPU usage than the other VST instruments.
http://www.hypersynth.com/