RV740 are 40nm with 640 Stream processors. It will replace the 4830.

The Radeon HD 4770 is equipped with 512MB of GDDR5 memories clocked at 800MHz while Radeon HD 4750 is equipped with 1GB GDDR3 memories. Core clocks for both cards stood at 700MHz. The RV740 cards will be the first series from AMD to feature Triple-Phase power solution for more efficient power design.

Radeon HD 4770 is expected to be priced at approx US$119 targeting GeForce GTS 240 while HD 4750 is expected to be priced at approx US$99 targeting GeForce 9600 GT.

This is 1 more reason to keep ur money in ur pocket