i have 4 samsung s e650 (1980×1080) connected using mini display port to display port 1.1 cables.
one screen does not give a picture. can you help?
Which HD7850 do you have ? Club3D CGAX-7856M6 ?
For a HD7850 card to be able to support more than 2 screens the Eyefinity Feature needs to be enabled. You do that by using a Displayport Output. OS needs to be WIN Vista or newer.
When using Screens with Displayport Input you can use Passive Adapters / Cables to connect from Card to Screen. (Although we always advise to use at least 1 active version, because in practice that seems to work better)
When using Screens without Displayport Input you need to use Active Adapters / Cables to connect Screen 3/4/5/6.
The first 2 are always natively supported so they can be connected with passive adapters at all times, although it will of course also work with Active Adapters.
Passive Adapters:
CAC-1100 = Mini DP to DVI Passive Adapter
http://www.club-3d.com/index.php/products/reader.en/product/29.html
CAC-1101 = Mini DP to HDMI 1.4 Passive Adapter
http://www.club-3d.com/index.php/products/reader.en/product/mini-displayport-to-hdmi-cable.html
Active Adapters:
CAC-1152 = Mini DP to DVI Active Adapter with Eyefinity Support
CAC-1170 = Mini DP to HDMI2.0 Active Adapter with Eyefinity Support
Technical Info on Eyefinity:
http://www.club-3d.com/index.php/technology/amd-eyefinity.en.html