Active Adapters to get 3 monitors with eyefinity working

[OllieBooton]

I have just purchased three identical monitors and three cables to hook them all up, I have monitors with hdmi and D-Sub connectors and have a graphics card with 2 mini display ports and an hdmi and a DVI. I decided to purchase two mini displayport to hdmi and one hdmi to hdmi cables to hook it all up. It came to it and now with all of them plugged in the third screen cannot be detected and therefore not configured into the display group. I have searched the internet and have heard you need to purchase an active adapter to display port to plug into the monitor, could someone please help me understand this, give me a link to one that i could use or even tell what i would need to buy. If anyone can help me It would be greatly appreciated.

 

[unknownofprob]

Mini DP to HDMI cables don't need to be active, I use one currently to connect my MBP to my monitor.

I use this:

Is this the cable your after?

 

[alexoiu]

Not sure if still valid for newer graphics cards, but since not working with passive adapters...
http://www.overclock.net/t/721931/active-vs-passive-displayport-adapters-the-truth

 

[OllieBooton]

I have two pretty much identical to that, 2 mini dp to hdmi and one black hdmi to hdmi however i have connected them all and only two activate and the other reads no signal, all the displays work and have tried moving the leads around but when we use catalyst control center it will show a small blacked out third screen but deny us the ability to incorparate it, any ideas

 

[unknownofprob]

AMD cards tends to need the user to setup Eyefinity to get the third screen working, try doing that.