Radeon HD 4770: New Graphics Chip from ATI
With a new, powerful chip generation, ATI is challenging Nvidia at the low end.
The new chip generation is called RV740, which ATI hopes to serve as a kind of test balloon for the next high-end RV870 chip. It's somewhat unusual to launch a new chip generation with a low-end model, which is not least of all why ATI describes its HD 4770 as "recession-proof." Technically the chip is a 40 nanometer RV770 chip (of the Radeon HD 48.0 generation) that AMD/ATI stresses is the first commercial chip of that size that its manufacturing partner TSMC has produced.
Because ATI raised the clock of the 128-bit memory bus to 1.6 GHz to get to to a reasonable 51.2 Gbytes/second memory bandwidth, no significant power savings should be expected. However, the Radeon HD 4700 can fall back to a 512-MByte GDDR5 RAM, GDDR5 being rather a novelty in the low-end market. Running at 750 MHz and with 128 unified shader units and 15 raster units, the 826 MIO transistor chip delivers a 12-Gpixels/second fill rate (24 Gpixels/second texture rate). It can also theoretically deliver, with 960 Gflops, twice the processing power of its direct competitor in the low-end market, the Nvidia GeForce 9800 GT. The HD 4770 is available now on graphics cards from numerous manufacturers at around $109 street price.