You will have to do better than that for the graphics. Radeons use four digits, not three, and the hundreds digit is the most important, with the thousand as next to least important.
An HD 4670, HD 5670, and HD 6670 are the successive numbers for three Radeon game cards in the 4n00, 5n00, and 6n00 generations.
Unusuable cards in recent generations include HD 4350, HD 5450, and HD 6450. Those are entry level cards for business use only.
For very high quality, the Radeon numbers have included the HD 59xx, HD 69xx, HD 79xx -- of course, those are very expensive.