If you are in the market for a new graphics card in the $300 range, the HD 4870 should be your weapon of choice. However, if you can settle with 16% lower performance (averaged over our testing), you may as well get the HD 4850 which runs quieter and offers more performance for your hard earned cash (performance per dollar). Even though you have to pay a premium for the extra performance, the AMD HD 4870 has the potential to revolutionize the $300 segment. It offers tons of performance to ensure all the latest games run silk smooth. If you plan on gaming on your big screen, the card is a good choice too. It supports a digital HDMI connection via the included adapter that also supports sound via HDMI. A novelty here is that 7.1 audio is supported as well, the previous HD 3xxx cards could only do 5.1 audio.
AMD has successfully introduced GDDR5 memory to the graphics market, which is a new generation of memory chips that is used on the HD 4870 for the first time. Compared to previous generations of GDDR memory this new architecture offers twice the bandwidth at the same clock and bus width. This means that AMD achieves over 100 GB/s memory bandwidth with a 256-bit bus while NVIDIA has to go 512-bits for that. Together with the link training features of GDDR5 this enables a much simpler PCB design, resulting in additional cost savings.
Several new power saving features were also added to the RV770 ASIC, but in my opinion these are not optimally configured at the moment resulting in higher power draw and more fan noise when the card is idle. Also, the low fan speed lets the GPU get quite hot, reaching temperatures close to 100°C under operation.