I never mentioned the D3X and never said it's high ISO output is better than the a900The A900 is just slightly more noisy than the Nikon D3x. Actually not bad when you know the A900 has a denser AA filter.The a900 ISO 6400 is not that great. So saying that the a77 is so close to the a900 ISO 6400 is may be not a compliment.