I am using a radeon 6950 Video card. I run two monitors just fine with the two DVI connections. (One of the monitors is using a VGA to DVI adapter, but that hasn't affected anything.) When I ever I try and plug in a third monitor to the miniDP port with a DVI to miniDP active adapter the screen on the third monitor flickers. I can see my desktop, but the monitor is unusable because it flickers so bad. I've tried different Monitors and different DVI cables and I still have the same problem. Any ideas as to what is going on? I have the latest drivers for my video card and everything.
There are 2 types of Active MiniDP to DVI adapters, one is unpowered one is powered.
Some people have had trouble with flickering on Unpowered ones that have been solved by using the ones with the extra USB power connecter them.
Though this has not solved everyone's flickering problems
Well I took my old adapter back and bought another one. This one is backed up by eyefinity and xfx. It's active and I hooked up my monitor with this instead. At first it seemed fine, then after 5 minutes it started to filicker every once in a while. It's not as bad as the other adapter, but It's still annoying. The one I saw with a usb was over 100$ WTF. If I decide I cannot handle the random screen flicker I might just have to hoof it with my two 22" 1920x1080 and 19" monitors. It's doable lol.
To conclude the post: I bought another adapter, this one was certified by xfx and eyefinity. It doesn't work perfectly. Sometimes there will be little random lines randomly popping up on it, but it works. I didn't need eyefinity to set it up either, I just used ultramon. Xfx customer support sucks. You have to go to their website and submit a ticket and they told me I needed to set it up with eyefinity. To say the least, for the amount of money I spent on the card, I'm pretty disapointed with Ati. Running three monitors should not have issues like this.