HD 4830 from MSI, the R4830
 

This is pretty astounding, really. At these clock speeds, using RivaTuner we were able to get more performance out of our R4830 than a stock HD 4850! To put things into further perspective, the R4830 stock speed is 585 / 900, so the stable 734 / 1121 overclock we obtained is a 28% / 25% increase. Generally, video cards average about a 5% - 8% overclocking average, and 10% - 15% can be considered a nice overclock for a video card. The only other card in the last one and half years of my tenure here at Neoseeker that overclocked nearly as good was the HD 2900 Pro.

http://www.neoseeker.com/Articles/Ha...Reviews/r4830/