The Radeon HD 5870 has 1600 shaders and runs at 825MHz. GDDR5 memory runs at 1050MHz compared to 1300MHz on the 5870 card and this results in a memory bandwidth of 140GB/s, which is more than the HD 4870. Updated
As you can imagine, ATI's Radeon HD 5850 card is a slower and crippled version of the Radeon HD 5870 and this slower card has 1440 shaders and runs at 725MHz.
Just like the Radeon HD 5870, this card comes with 32ROPs and the maximum power consumption is 170W under load and 27W when idle. The launch date is September 23rd.