I have contacted Club3D for support regarding this issue, they claimed to have spoken to AMD and here is the official statement:
Sorry for the late reply, we have checked this out with AMD.
Both ports on the card does support DVI-D dual link.
However when you connect them together it does not work on the 1440p resolution.
One port will scale down to 1080p, the other remain at 1440p.
All 200 series chipset, like 290x, 290, do have this limitation.
The only way that you can get it to work here is to connect the display with the HDMI or DP output.
This is definitely disappointing news, then what's the point of having 2x DL DVI ports, what a big troll. Anyhow my card doesn't even scale down to 1080p on the secondary monitor, but it doesn't matter I have now gotten a GTX 980 TI, and surprise surprise, drivers and display works on the first try without a reboot amazing ...