There are too many variables to simplify it down that much. Everything from the number of stream processors to the type of memory to the memory clock to the core clock matters.
Of the ones listed, the HD4670 is by far the best card. The Nvidia 9600GT is pretty close to it in performance, and the HD4830 and 9800GT are better than all of them.
It's better because of a combination of the architecture, the number of stream processors (320 in this case), the core clock, and the memory clock. As a general rule, avoid cards with GDDR2. However, this doesn't guarantee that a card with faster DDR3 will always be the best. It needs to have a combination of factors, not just one thing.
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