RV770 will launch as Radeon 4800 and will make its way into the FireStream stream processor and FireGL workstation cards. Both GDDR3 and GDDR5 memory will be supported by the chip, but ATI itself will only be offering GDDR5 cards. The Radeon 4850 version is set to come to market with an 800+ MHz core (the final clock has not been specified yet and will not be available until the final qualification is completed), while the 4870 will be the first mass-production GPU with a clock speed higher than 1 GHz. Prototype RV770 boards were clocked at about 1.05 GHz.
The graphics processor itself will integrate more texture memory units (TMUs), which is the Achilles' heel of the R6xx generation: 32 TMUs in the RV770 will challenge the 56/64 units of Nvidia’s G92/G92b.
The new graphics card generation is expected to become available to system integrators and OEMs in GDDR3/GDDR5 variants with 256/512/1024 MB buffers. 256 MB GDDR3 cards are exclusively targeted at OEMs (as well as ODMs, Sis) and are unlikely to shop up in retail. Expect to see mainly 512 MB GDDR5 cards in retail for both the 4850 and 4870. Just like the GPU, the memory clock isn't set in stone either, but we were told that the GDDR5 memory is currently running at a physical clock of 1.8 - 2.2 GHz.
With a 256-bit memory controller, we're talking about 115 to 141 GB/s of bandwidth. This number equals the memory bandwidth record set by the 2900XT 1GB GDDR4 (512-bit interface with GDDR4 at 1.1 GHz DDR).
