OCC has published a new review on the PowerColor HD 4830

Wow was I surprised when I got to overclocking this baby. She took everything I threw at her and begged for more. Using the Catalyst Control Center I was able to increase the core speed from 575MHz to a whopping 670MHz almost 100MHz increase. Not bad for a little card like this. As expected the memory came close to the rated 1GHz limit topping off at 995MHz ( 1990MHz Effective ). This card easily reached these speeds by upping them in 5Mhz increments each until it became unstable and then I backed off 1MHz at a time until I had no more issues or display problems.

PowerColor HD 4830 Review