AMD is hoping to release the ATI R680 GPU in January 2008, VR Zone reports. This chip will offer DirectX 10.1, Shader Model 4.1, PCI Express 2.0, UVD support and next-generation CrossFire support.
It's said that the R680 will have 320 stream processors like the R600 and support for double precision floating point.
Other sources add that the chip will have a frequency above 800MHz and 512MB or even 1GB of GDDR3 memory.
Most likely it will come with 512-bit memory interface. Along with R680, we should be seeing RV635 and RV620 replacing HD 2600 (RV630) and HD 2400 (RV610) respectively as well as HD 2950 Pro (RV670) to form a complete top to bottom line-up.