The specifications of the ATI Radeon HD 4550 were leaked today. Expreview published slides which unveils this card will feature a 600MHz RV710 core with 242 million transistors, that's about half of the RV730. The upcoming Radeon HD 4550 has just 80 shaders, while the new Radeon HD 4650 has 320 shaders.
There are two versions of ATI HD 4550, 512MB and 256MB versions. Both version have a reference board, 512MB is a full hight card and 256MB is a low profile. 512MB version have DVI/HDMI/DP output, and 256MB supports DVI/S-Video/D-Sub output. Both versions are running on 600/800MHz（Core/memory）.
Basically speaking, RV710 is a shrinked RV730, only two SIMD (single instruction multiple date) array, each of them have one texture unit. Inside each texture unit there are 4 Texture Address Unit, and 4 Texture Filter Unit. So in RV710 there are totally 8 TA and 8 TF units. Also there is only one Render Back End and memory bandwidth is lower to 64bit.
The card will be available by the end of the month and will compete against the GeForce 9400 GT. The Radeon HD 4550 512MB debuts for $49-59 while the 256MB card will be priced at $39-49.