Dell latitude 3540

Hi! Acording to the online specs this laptop has Intel's HD Graphics 4400 GPU and AMD's Radeon HD 8850M graphics chip, but in device manager is just the intel graphics and when i try to install the amd driver , the amd auto-detect isn`t recognizing the video card. In dxdiag it shows just the intel graphics nothing about the radeon s 8850m . It`s like the video card isn`t there at all. What should i do ?