PCSX2 is a PlayStation 2 emulator for Windows and Linux. It was started by the team behind PCSX (an emulator for the original PlayStation) back in 2002, and as of early 2012 development is still active. The emulator achieved playable speeds only by mid-2007 and subsequent versions have improved speed and compatibility making it both the ultimate solution for PS2 emulation and the instrument to keep and preserve the PS2 legacy in the modern world. Though not yet perfect the program can successfully emulate most commercial PS2 games at playable speeds and good visuals (often better than the original PS2). The project is open source, and it is licensed under the GNU General Public License v3. Currently up to 3 cores are supported (2 cores and an additional one if the new MTVU speed hack is used). To make PCSX2 efficiently use 4 or more cores will require major code changes. PCSX2 only uses 2 cores,so if you have more the CPU usage will be way less 100%. Even if you have exactly 2 cores, the emulator will not cause 100% CPU usage because of the way threading works. This does NOT mean PCSX2 isn't using the full power of your CPU, it is normal.
