"After seeing the results that the custom cooled MSI HD4850 delivered on the overclocking front I was eager to see if I could duplicate that same success on a reference card. The answer is no I could not, but I came close. After all the time spent searching for that ideal mix betweeen GPU core clock speed and the memory clock speed I was stopped at 675MHz on the GPU core and 1075MHz on the memory. Not massive clock speed increases but enough to go to the mat for it. With these increases came the corresponding increase in performance. Seen mostly at the higher end of the gaming benchmarks. By comparison, the clock speeds for the MSI card were 25MHz higher on the core and 1187MHz on the memory. Close, but no cigar on beating those clock speeds. To get the clock speeds of 675MHz on the GPU core and 1075MHz on the memory I used a software application called AMD GPU Overclock Tool to make changes outside the range available in the Catalyst Control Center."