i´m thinking about an Update from GTX580 to HD7970, useful or just wasting money? actual system: 2 x X5650, 48GB RAM, 1 x GTX580, 2 x HD5870 Eyefinity 6 (=> Problems using AMD&NV, AMD driver crash) new system: 2 x X5650, 48GB RAM, 1 x HD7970, 2 x HD5870 Eyefinity 6 Before i used a HD5870 as main...