When trying to capture the information on the MSI HD4830, we ran into an odd issue with GPU-Z, as shown above. GPU clock of 143056MHz and memory of 47841MHz was seen in the above image. The numbers seemed to change randomly each time I launched the program, so I went to ATI Overdrive for overclocking duties.
Using the built in overclock utility, the HD4830 ran up to 700MHz GPU without so much as blinking. On the memory clock side, we were able to get to 1100MHz on a couple tests, but for a stable overclock, I settled at 1000MHz. Even when pushing up around 700/1100MHz, the temp meter in ATI Overdrive never peaked beyond 43 deg C and the fan was able to stay fairly quiet.