Hii,

I must say that I’m impressed from both companies. The GTX280 has over 4000 points in 3DMark Vantage which is extremely high. When the mid-range card of ATI, the 4870XT still can give you a nice 2600+ points at a very high resolution and quality settings (1920x1200 - 4AA and 16AF). Their high-end graphics card will be two 4870XT paste together. The score will probably be higher then the score of the GTX280

Article:
Both the GeForce GTX and Radeon HD 4800 series will arrive in about three weeks. Each series will bring two new cards to the market; GeForce GTX 280 and 260, and Radeon HD 4870 and 4850. There is a big difference between the cards though as the GeForce GTX series is enthusiast range, while Radeon HD 4800 series is more mid-range. There have been talks of what GeForce GTX 280 can do in Vantage, but it has now been completed with figures for the other cards.

These are of course in no way official and we can’t say for certain where they come from. The only thing we know is that the numbers are not unreasonable, but some information about the rest of the system would be nice. ATI performance (with all cards) is still subpar due to poor drivers, and should improve in Vantage with coming releases. The numbers that are circulating the web are something like this;

Graphics card  
Vantage Xtreme profile*
GeForce GTX 280  
41xx
GeForce GTX 260  
38xx
GeForce 9800GX2  
36xx
GeForce 8800 Ultra  
24xx
Radeon HD 4870 XT  
26xx
Radeon HD 3870X2  
25xx
Radeon HD 4850 Pro  
20xx
Radeon HD 3870  
14xx
* 1920x1200 4AA/16AF

Source can be found here