The Falcon NorthWest Mach V and Hardcore Computer's Reactor are two of the fastest and most interesting overclocked gaming desktops we've ever seen at PC World. The Reactor has a custom-designed case that's filled with non-conductive oil to cool the system, while the Mach V has a 3.2 GHz Core i7 processor that's overclocked to 3.8Ghz. Senior Associate Editor Danny Allen takes a look.