Cynicism and High Resolution Monitors#


When last we left my latest journey into the realm of the resolutionally absurd, I had a couple of large boxes on the floor, one of which contained an Apple 30" Cinema display. This display uses dual-link DVI, which has been around for awhile, but is not widely understood. The reality of the DVI system is that it supports a lot of different modes, and dual-link is the most powerful and most expensive of them. Inside a dual-link DVI cable is two entirely separate sets of video signals. This is necessary to handle the 2560x1600 resolution of the Apple 30" Cinema display. A single-link DVI pretty much maxes out at 1920x1200.

So to drive the Apple 30" Cinema display at 2560x1600, I needed a dual-link capable video card and a dual-link cable. The display came with a six foot hard-wired cable, much to my annoyance, since I nee at least twelve feet of cable to reach my workstation bay. That meant finding a dual-link extension cable.

You'd think finding a dual-link video card would be easy, and you'd be right, unless you wanted assurance that you're actually getting one. It used to be that dual-link DVI was a rare and expensive feature, requiring you to order specific cards for the purpose. That's not true anymore: pretty much every nVidia 7800 series video card supports dual-link, its so common that its not mentioned anywhere in the specifications or documentation at all.

So, when I looked at my situation: new monitor, unfamiliar cabling protocol, fixing wiring with an extension and utilizing an essentially undocumented feature of a video card, I figured there was no hope in hell of it actually working. Cynical? Perhaps. But just because you're not cynical doesn't mean you aren't screwed.

And realize that the machine I wanted to rebuild is my main workstation - granted I have backup machines, but taking the main workstation down is not something I do casually.

So, I built a testbed. Left the existing machine entirely alone and bought the parts to rebuild it, with the intention of testing all those parts independently of the existing machine.

Since I was going to need two video cards, one to drive the Apple display and the other to drive the two wing displays, I wanted to get a motherboard with two PCI-Express slots in it. This means an SLI board like the ASUS A8N I currently had in my gaming system. Normally SLI uses two video cards to run one display, thereby doubling the frame rate. For my purposes, I'd be using two video cards independently, but with symmetrical performance. Sure, I could have done this with one AGP card and one PCI card - but that would suck. Dual PCI-E is the way to go.

I chose the ASUS A8N32-SLI motherboard for the job, and just for good measure, plugged an AMD 4800 Dual Core in it. Hey, two video cards deserve two processors, right? The video cards I chose are MSI's implementation of the nVidia 7800GT. These are high performance video cards, but not top of the line: I'd had enough of the heat problems with the 6800 Ultras to know better. These are great cards, lots of horsepower, but not so much that they're running in a state of near meltdown.

So, to build the test bed, I rigged up the motherboard with the processor, some spare RAM I had lying around, a hard drive and DVD player. Just sitting there at the service desk on a towel. I stuck one video card in it because I wanted to work out the first issue: could I make the Apple 30" Cinema display work in 2560x1600 mode with an extension cable. The list of failure points was long, but the key ones were whether or not I had the right video card, and whether or not 2560x1600 signals would travel through an extension cable and still be bearable on the far end.

Here's what the rig looked like:

You might just spy the screwdriver stuffed under the back of the board. The video card sticks down enough that it was popping itself out of the slot when I was testing, freaking me out when suddenly nothing worked. Getting the "machine" up and running wasn't all that difficult. I first fired things up with the video card plugged into the little 15" LCD panel you see sitting behind the board. Once I was sure the basic configuration worked, I fired it against the Apple display without the extension cable.

That worked as well, so I went ahead and did an install of Windows XP. This takes awhile, between the hard drive formatting and basic install. The rig was plenty quick. Once the base OS install was finished, I focused on video drivers. This was best done by getting network drivers running first, and downloading the latest video drivers.

640x480 on a 30" display is hilarious - the icons are the size of your fist. Then I got the nVidia reference drivers installed, and the resolution bumped up to 1280x800. Better, but not what I wanted. My mistake was plugging the display into the top connector on the video card: only the lower connector has dual-link support. Once it was down there, I got this:

And just in case you can't read it clearly:

Final test was the extension cable. Plugging it in was fine. The screen was clear and stable with and without the extension cable. On reboot, the starting low-resolution screens had little bits of distortion in them, but as soon as it kicked into high resolution mode again, it looks perfect.

So, tests complete, I guess I'm ready to tear apart some gear and get these new displays integrated into the office.

Sunday, February 12, 2006 3:46:18 PM (Pacific Standard Time, UTC-08:00) #    Comments [3]  |  Tracked by:
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