radeon hd 3870 & 3850

 

AMD’s two new graphics cards starts today, both on a new GPU, internally as the RV670. The basic architecture of the hardware is largely unchanged from R600, there were some additional features added, and a great deal of internal bandwidth, but other than that this is a much R600 based.
The largest part of this news is that it happens on a fabbed TSMC 55nm process. It is a half-node process based on 65nm technology, the AMD an advantage in the (cost) size and potentially clock rate and / or electricity.

Historically, AMD’s RV series has been a cost reducing their version of the R-series, the volume of parts for the lower end, and that is where RV670 begun. Right of the bat, half of the external and internal memory bandwidth of the R600 was cut. External bandwidth fell from 512 to 256-bit bit, but AMD memory stuck with 8 channels (each fell from 64-bit to 32-bit).

Internally, the ring-bus declined from 1024-bit and 512-bit encryption. This reduction in the bandwidth to a significant decline in the transistor count of R600’s ~ 720M. RV670 is composed of 666M transistors, and this includes the addition of UVD hardware, some energy-saving features make the necessary additions for DX 10.1 and the normal performance improvement, we would expect another iteration of architecture.

Processing power remains unchanged from the R600, RV670 functions Stream 320 processors, 16 texture units and 16-speaker again ends. Clock rates have slightly and memory speeds have increased tremendously to get closer to the memory bus.