Little Boy and Fat Man, the two bombs that changed the world as we know it. First Little Boy was dropped on Hiroshima and then Fat Man was dropped on Nagasaki to end World War II. You have to ask, what does a World War II lesson have to do with video cards? ATI dropped the first bomb with the release of the HD 5870 with clearly superior results over the previous generation ATI products and a commanding performance lead over the current top of the line nVidia single GPU video card, the GTX 285. Now Fat Man has taken flight with the release of the HD 5970. Clear in its sights is the top of the performance ladder for nVidia, the GTX 295. Each of us remembers the introduction of ATI'sdual GPU behemoths, the HD 3870x2, HD 3870x2 and the HD 4870x2 and the performance they brought to the table. The 3870x2 gave ATI some high end punch followed up later in the year by the HD 4870x2 to increase the level of performance before the launch of nVidia's GTX 295. From that point the green camp has been wearing the performance crown in the single video card battle. Things look to be a changing! ATI has chosen to go a different route with the naming of this card because it really is not a dual 5870 or 5850 but a combination of both. How is that? It has the hardwarefrom the 5870 doubled up but runs with the clock speeds of the HD 5850 to keep the power consumption and thermals in check even though the heatsink can handle a total of 400 watts. Much like the rest of the HD 5XXX family, the HD 5970 supports DirectX 11, Open CL and ATI's Eyefinity multi-display technologyfor an added level of immersion.Sapphire has chosen the route of opening this salvo with an overclocked model for that extra added punch. The Sapphire HD 5970 OC 2GB comes equipped with a total of two RV 870 Cypress cores that have a total of 3200 Stream processors, delivering almost 5TFLOPs of processing power, making the HD 5970 the most powerful video card on the planet. Clock speeds come in a bit higher than the reference versions at 735MHz on the two Cypress cores and 1010MHz (4040MHz effective) on the 2GB of GDDR5 memory. Each core has 1GB of memory dedicated to it, running through a 512-bit bus (256x2). The specifications on paper look impressive, but that's not all; gone are the overclocking limits we have seen in the past as this card comes unlocked so you can throw the screws to it to gain some more FPS or distributed computing power. This card is designed to do some hardcore overclocking based on the construction. It features multiple Volterra voltage regulators, Japanese made pure ceramic SuperCapacitors, real time power monitoring and a programmable fan controller. The cores used are "low leakage" parts so you can get the best parts to push. With many HD 5870s hitting 1000MHz on the cores, overclocking should prove interesting. Let's take a look.