Basically this will be a cut down HD4890 with a 700mhz core and 640 stream processors:
http://www.techpowerup.com/100337/Ra...he_Works?.html
It seems that this will replace the HD4850.The HD4830 has also been replaced by the HD4730 and HD4770 too. It seems ATI is trying to shift as many of its products as possible to GDDR5 RAM. It also looks like ATI is trying to make use of as many of its defective cores as possible before its DX11 releases it seems or either 640 stream processors seems to be the sweet spot for ATI or something like that as the HD4730,HD4770 and HD4860 all have this number of stream processors!!??
Now we have from ATI under £100:
1.)HD4730 - cut down 55nm RV770 with 640 stream processors running at 750mhz and a 128 bit memory access with GDDR5.Two power connectors.
2.)HD4770 - 40nm RV740 with 640 stream processors running at 750mhz with a 128 bit memory access with GDDR5.One power connector.
3.)HD4830 - cut down 55nm RV770 with 640 stream processors running at 575mhz with a 256 bit memory access with GDDR3.One power connector. EOL?
4.)HD4850 - 55nm RV770 with 800 stream processors running at 625mhz with a 256 bit memory access with GDDR3. One power connector.EOL?
5.)HD4860 - 55nm RV790 with 640 stream processors running at 700mhz with a 256 bit memory access with GDDR5.One power connector.
6.)HD4870 - 55nm RV770 with 800 stream processors with a 256 bit memory access with GDDR5.Two power connectors.
All these graphics card releases from ATI in such a short time is confusing people.