Hardware Requirements
Hardware requirements are largely game-dependant although the performance bottleneck of this emulator in most cases is the CPU rather than than the GPU: in short, having a computer with a faster CPU should net you better PCSX2 performance. Some games however may run slower due to unoptimized GFX code or weak GPU cards.
A common misconception is that a higher CPU clock speed guarantees improved emulation performance. Although clock speed is one of the main factors for good PCSX2 performance, it is not the determining factor. Newer CPUs generally perform better than older ones at similar clock speeds. For example, a 2.4 GHz dual-core Intel Core 2 processor will generally outperform a 3.2 GHz dual-core Intel Pentium D processor. Even though the Pentium D is clocked higher, the Core 2 Duo is faster due to the Core microarchitecture of the Core 2 Duo being more efficient than the Netburst microarchitecture of the Pentium D. This is true of many modern Intel vs AMD processors, as the high-end Intel processors are more efficient than the high-end AMD processors. Because PCSX2 only uses two main threads, having a CPU with more than two cores does not significantly increase PCSX2 performance. Performance can be improved up to 70% by enabling the multi-threaded VU (MTVU) hack in the Speedhacks menu, which will use an additional third thread (thus mostly useful for CPUs with more than 2 threads).