Originally Posted by C-zom
You'd be surprised how common the leap is, it's usually almost double or a bit more than. The 7800 to the 6800 was the lowest jump. But the 7800 to 8800 was more than double, the 285 to 8800 was double (over, once drivers aged). That's just using Nvidia's cards.
if I had to take a not very educated guess, chalk me up for 7800 to 8800. If there had to be a favorite, I'd say the jump from x800 to x1900 was fantastic too.