That's just not true. 4830 isn't all that much slower compared to a 4850. The 4830's are known to be pretty good OCers and have near 4850 performance for much cheaper. 4850's don't OC well. A 4870 would be an improvement for around $150, but for the $75AR that he probably got that card for, a 4830 is definitely a good buy.
Do you have some proof to backup those statements? As far as I am concerned the HD4830 is just a next gen 8600GT.