Here are the overclock results I was able to gather. I scooped these numbers up while skipping to Grandma's house and I arranged them in pretty table for you.
I compared a HD 4830 clocked at 760/2,210 to a reference HD 4850 and in some ways, the overclocked HD 4830 has faster rates or more bandwidth.
|Memory Bandwidth||FLOPS||Pixel Fill Rate||Texture Fill Rate|
|HD 4830 OC||70.7 GB/sec||972.8 GFLOPS||12,160 MPixels/sec||24,320 MTexels/sec|
|HD 4850||63.552 GB/sec||1,000 GFLOPS||10,000 MPixels/sec||25,000 MTexels/sec|
With that in mind, I should remind you that you can get a Asus HD 4850 for $5 more ($135) than the HD 4830.