U2713HM maximum resolution and auto-adjust issues

"Display Port cable which was *not* included with the screen."
* True. We stated in the User's Guide page 6 that we would only ship the following cables =
Power, VGA 2048x1152 60Hz, DVI-D DL 2560x1440 60Hz, USB
ftp://ftp.dell.com/Manuals/all-products/esuprt_electronics/esuprt_Display/dell-u2713hm_User%27s%20Guide_en-us.pdf

"The Dual Link DVI cable is completely useless as the maximum resolution it allows is 1920x1080."
* The U2713HM DVI-D Dual Link port can do 2560x1440 60Hz using our DVI-D Dual Link cable, but, the video card and its port must support that resolution. So if the video card port is only DVI-I or DVI-D Single Link, you will only get 1920x1080.

The most aggravating issue: using the VGA cable (which at least allows a better resolution than DVI), if the computer is booted in Windows it will flash an "auto-adjustment in progress" message once and then get stuck on a blank screen.
* Using VGA will result in the the ability to use the Auto Adjust in the U2713HM OSD (On Screen Display). But it should not result in a blank screen or an automatic auto adjust? That points to the video card driver making those adjustments. Are you testing the VGA cable that came in the U2713HM box?

The video card should support 2560x1440 via Dual-link DVI according to the specs (http://www.amd.com/en-us/products/graphics/desktop/oem/8570). As the problem arises on two different machines with the same video card, I don't think it's a defective video card. The only reason I thought of trying with the display port cable is because I found several threads online by users with the same problem who solved it using a display port cable. However, I want to set up two monitors per machine, and I'm not sure whether this is possible via display port?

Yes, I have tested several VGA cables that all came in the monitors box (we ordered four screens so I have plenty of spares to test) and all of them result in the automatic auto adjust issue, but only when booting into Windows. Ubuntu works fine.

I said that the video card driver was suspect, not the video card. I would test different video card drivers. I would start by re-installing ours:
http://www.dell.com/support/home/us/en/04/Drivers/DriversDetails?driverId=8CF2V

Then I would test the retail drivers.

I have already tried uninstalling and reinstalling the drivers with no luck. VGA still gives the auto-adjustment/blank screen problem with Windows and DVI doesn't go higher than 1920x1080.

I do not think this is a monitor fault. Go to the AMD website and search for older drivers to test.

I have tried different drivers and nothing solved the issue.

However, searching different forums, I found some users claiming that the AMD Radeon HD 8570 that comes in the Optiplex 9020 does not support  2560x1440 via DVI, despite the specs of the card on the AMD website claiming that it does. Allegedly, this is because the version of the card that AMD makes for Dell is a lower-end version, despite having the same product code (see here: http://en.community.dell.com/support-forums/peripherals/f/3529/t/19524355.aspx).

Are you able to confirm or deny this? 

If this is the case, and I can only set up the display using a DP cable, is it possible to set up dual monitors both at 2560x1440?

Regardless, this does not explain the auto-adjustment problem via VGA. 

All Dell video cards are OEM (original equipment manufacturer). The retail video card specifications do not apply to Dell video cards. With only one DP on the video card, you can only run one monitor at 2560x1440. The second monitor on the DVI-I (NOT DVI-D) will be at a lower resolution 1920x1080. The second monitor on the VGA will be at 1920x1440. I do not know why the VGA auto-adjust is occurring.

I had a chance to try out the monitors on a different machine with a different video card (using the same cables that came with the monitors), and it picked up the resolution right away. So I'm inclined to rule out the monitors as the issue (although some have reported the same problem with the same monitors but with different videocards, see here). 

The HD 8570 is OEM only, there's no retail version, as specified on the AMD website. This should, technically mean that the specs reported here are the specs for the Dell HD 8570 <ADMIN NOTE: Broken link has been removed from this post by Dell> that came with the Optiplex. However, Dell does not specify resolutions for the card on its website - at least, not that I can see - so how can one confirm what resolution is actually supported by the 8570 provided by Dell?

Thanks for that, Chris. I'm confused then. There seems to be a discrepancy between the specs reported here and the card I have. 

These specs seem to indicate that the card comes with a single-link DVI port, but the port on my video cards is definitely dual-link DVI. It looks like the bottom one in the image below, not the top one:

Also, with VGA I can achieve a much higher resolution than 1920x1440, in fact I achieve the maximum resolution reported by AMD on their website, which is 2048x1536 (but I run into that auto-adjust issue so can't really use it at the moment).

I agree that the port is DVI-I Dual Link, but not all of the internal post in that port are turned on. Your 1920x1080 results back this up. The 9020 sold with these two video cards that can do 2560x1600 on their DVI-I Dual Ink port.

J53GJ AMD Radeon HD8490
X1F5R Nvidia GeForce GTX 645

Or simply buy a retail video card that has a true DVI-D Dual Link port. 

Is there anywhere on the Dell website where I can find the info from that screenshot you posted? 

I've been looking around and couldn't find it, and I asked our IT dept who have placed the order for us and have access to a more comprehensive version of the website for purchases, and they also told me they could not see any detailed specs about the card other than the one I previously linked. 

Also, I understand how the DVI might  not support 2560x1440 if it's not be a true dual-link, but how can the VGA support a higher resolution than specified as maximum?

Will do, thanks. 

I think it would be good to add those specs to the online info about the card though, as it's a fairly important factor before purchasing. We would have gone for another card right away and saved quite a lot of time.