Q4000 = NVIDIA Quadro 4000 GPU (1 power feed, 2G VRAM) R5870 = AMD Radeon HD 5870 (2 power feeds, 1G VRAM) Q6000 = NVIDIA Quadro 6000 GPU (1 eight pin or 2 six pin power feeds, 4G VRAM) ** GTX 680 = NVIDIA eVGA GeForce GTX 680 GPU (2 power feeds, 2G VRAM) GTX 570 = NVIDIA GeForce GTX 570 GPU (2 power feeds, 2.5G VRAM) ** GTX 580e = NVIDIA eVGA GeForce GTX 580 GPU (2 power feeds, 3G VRAM) **
GTX 580+ = NVIDIA 'Classified' (overclocked) GTX 580 GPU (3 power feeds, 3G VRAM) **
