Gigabyte HD 3850

ATI's HD 3800 series appeared on the market a little over a month ago, and provided the buyers with an excellent value for money, especially since they are positioned between NVIDIA?s 8600 and 8800 series, and that?s a pretty big price gap that NVIDIA didn?t manage to fill. So if you can?t really afford an 8800GT, the two 3800 cards are right there for you. Today, we will be looking at the cheaper one, the HD3850 from Gigabyte.

ATI?s RV670 is designed as a cheaper version of the R600 GPU, which can be found in ATI?s first DX10 card, the 2900XT. 2900XT was a bad product, for several reasons. First, there was performance, since ATI didn?t manage to even come close to NVIDIA. Second one was price/performance ratio, since 2900XT was slower and more expensive than the 8800GTS 640. And third, the enormous heat it produced required a big and loud cooler. RV670, while not a direct successor to ATI?s flagship, gets rid of almost all the problems. It is produced by TSMC using a half-node 55 nm process, down from 80 nm used in R600. The 55nm process is responsible for the much lower power consumption, so ATI can now put only one PCI-E 6 pin connector on a card, unlike the previous one which had one 6 pin and one 8 pin connector for a total of 250W of power. Although HD3800 series is PCIE 2.0 compatible, they still require less power. Less power always means less noise, and in this case also means that the cooler can be of a less complex design, which reflects on the card?s price. Aside from the decrease from 80 to 55nm, ATI saved money equipping this GPU with only a 256-bit wide memory bus, and a 512-bit internal bus, which is exactly half of the R600. Everything else remained the same, so the chip has 320 stream processors, 16 texturing units and 16 render back-ends. After more than 6 months, some new features were made available, so RV670 now supports DirectX 10.1, which a few extra features to game developers, but we have yet to see any titles that support this. If game developers are as quick to implement them as they were with DX10, we will wait awhile. Even Microsoft will enable DX10.1 support in Windows Vista only with SP1, which is scheduled for H1 of 2008.

RV670 also supports UVD, which is its own video decoding engine, capable of supporting VC-1 and H.264 formats that are used in Blu-Ray and HD-DVD video content. Unlike NVIDIA?s PureVideo, UVD supports entropy decode for VC-1 video, but it is not a groundbreaking feature since VC-1 is less demanding to decode than H.264.

The RV670 also supports PowerPlay, which is a form of power management that modifies the clocks and voltages of the core if there is no need for extra performance, something that is normally seen in mobile graphics cards. AMD states that unlike on previous products, all 3D applications can make use of the full processing power of the card that was previously only reserved for full screen 3D applications.