This can be a significant speedup on CPUs with 3+ cores, however on GS limited games (or on dual core CPUs) it may be a slowdown As of r4865 PCSX2 can now take advantage of a 3rd core using the MTVU speedhack. Note: PCSX2 mainly takes advantage of 2 CPU cores. Note: Because of copyright issues, and the complexity of trying to work around it, you need a BIOS dump extracted from a legitimately owned Playstation 2 console to use the emulator.
IMPROVE PCSX2 EMULATOR FULL
Once able to run only a few public domain demos, recent versions enable many games to work at full speed, including popular titles such as Final Fantasy X or Devil May Cry 3.
The PCSX2 project has been running for more than ten years. It's purpose is to mimic the the PS2 hardware, using a combination MIPS CPU Interpreters, Recompilers and a Virtual Machine which manages hardware states and PS2 system memory. PCSX2 is an open source Playstation 2 emulator.