Last week saw AMD complete their high-end Radeon HD 5000 series strategy with the launch of the dual-GPU Radeon HD 5970, taking the single graphics board performance crown with them as they went. Today we take a look at Sapphire's Radeon HD 5970 Overclock Edition, to see what this new flagship part brings to the desktop 3D graphics market, and whether it's a must-have purchase for the hardcore gamers and enthusiasts amongst you.