Nordic Hardware has obtained some interesting information regarding the memory configurations of AMD's upcoming RV710 and RV730 GPUs:
"V730 and RV710 are the code names of the mid-range and low-end GPUs of the Radeon HD 4000 series. A document provided to us sheds some light on the upcoming cards using these GPUs. The memory configurations are listed as well as the specific memory type. AMD is trying out a number of configurations, but we can safely say that you should be expecting two different cards based on either GPU, with varying memory speeds or capacity.
Two different GDDR3 memory configurations can be seen with RV710. Both memory operates at 800MHz, but the density varies from 512MB Hynix memory to 1024MB Samsung chips. This points to that the 4450 and 4470 models will be separated by GPU clock. We need to confirm the exact specifications of both RV710 and RV730 before revealing more about them. No 256MB models could be spotted in the document.
RV730 offers a bit more variation as we notice three different clock frequencies and two different densities. One 700MHz 512MB model, and two 900MHz models, whereof one sports 512MB Hynix memory and one sports 1024MB Samsung chips. Last but not least there is one model with 512MB Hynix memory operating at 1000MHz. We would assume Radeon HD 4650 is the 700MHz cards, while the 4670 model is represented by the three remaining cards.
We can also see a couple of new RV770 cards with the memory running at 990MHz and 1000MHz. Diamond has already launched a card with memory chips operating at 1100MHz, and hopefully there will be additional models with the memory frequency upped a bit. We hope to post some more hands-on information with the Diamond Radeon HD 4870 XOC Unlocked Black Edition soon."