Arroneus,

Simplify the troubleshooting setup. Power the computer and both monitors off. Disconnect the 2nd monitor and DP cable from the video card. Setup only one monitor to the video card via DVI to DVI. Power on that monitor, then the computer. In this single monitor setup, can you set the desktop resolution to 2560x1440 at 60Hz?

If yes, while the computer and primary DVI monitor are turned on, power on the secondary DP monitor, connect the DP cable to the video card. Go into the display settings and enable the secondary DP monitor as extended.

Chris,

I went through the process as you recommended, but unfortunately the lone monitor connected via DVI could not be set higher than 1080p resolution. 

To me this implies either that either the cable that came with both of these monitors is defective and only carrying single DVI signals, or the graphics card is defective and only detects the lower resolution capability, or there is a setting somewhere to make it acknowledge the actual resolution that is not properly set. 

-Aaron

I think it's most likely something with your video card and/or driver than the monitor itself. 

I have used GTX680 and AMD HD7870 with DVI-D Dual-link for a long while and did not have issue with resolution - in fact DVI-D is usually the more stable connection method.

AMD 8570 is not exactly high end so the tests with high resolution configurations may not be as though as it should be, you may want to borrow a higher end piece to test it out.

You are right that it should work according to the specs on the products.  But what I (and most people) didn't know is that Dell puts lower-end versions of various hardware in their machines.  So the Dell version of the AMD 8570 card, even though it has the same model number, has worse performance than the one described on the AMD website.  I received an e-mail from AMD and they told me that the version of that video card made for Dell does not support Dual-Link DVI. That's the reason it didn't work. But thankfully it works using the Display Port 1.2 connection. Wouldn't it be reasonable to list the video card as a different model number if it performs differently? And in addition they need to be more explicit and more detailed in the listing of the tech specs.  All computer companies and retailers are bad at this (e.g. not posting specific resolutions and DPIs), and Dell may be worse because they are big enough to have versions of standard hardware made for them.  Considering the importance of computers for modern society, I can even imagine some sort of regulation being imposed on listing specs akin to the Nutritional Information standardization we saw on foods. Anyway, no thanks to Dell or TIG (my retailer), I've solved the problem with the help of AMD.

Glad to know your issue is somehow solved.

I am not an Dell employee (apparently) but in Dell's defense - the specs listed on Nvidia/AMD/Intel website are usually max configurations, most lower cost/OEM parts tend to cost down somewhere - hence the lower cost.  In general if you are shooting for the latest/best spec for monitors, higher grade video cards usually save a lot of issues.

But of course if you can prove that Dell has advertised Dual Link, I am sure you can get a refund - even if they don't, it's still possible to get a refund, I assume your piece is relatively new.

Good luck.