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Monitor Resolution with DVI-D Dual Link

02-07-2009, 10:51 AM
So I bought a new (lightly used) LCD monitor: an HP w2007. I connected it up to my laptop's extension bay (my laptop is a ThinkPad T-60 running Vista) with a standard (and well-used) VGA cable. The picture had a fuzzy green tint (either due to incorrect sync or a bad cable) so I bought a new DVI-D dual link cable to connect my laptop via its extension bay to the monitor.

After going through all this I tried to put my resolution to the monitor's native resolution so I could calibrate the colors and whatnot (fortunately the green was gone) but instead of increasing the display resolution to 1680x1050 (and 32 bit color) the whole display just went black, and the highest resolution the display can 'do' without going black is 1024x768 (32 bit color) or 1280x720 (16 bit color). I know the card is capable of some version of 1680x1050 (32 bit) because when I had the VGA cable hooked up it could display that resolution fine (ignoring green tint). My monitor is the only display active (the laptop's display is inactive).

My only and best guess is that somehow the DVI-D dual link requires more graphics resources to operate than the VGA connection, and the graphics card with my T-60 is rather weak: ATI Mobility Radeon X1300 with 64MB of dedicated video memory and 767MB of shared system memory.

How can I make it so that I can use my monitor at (or at least near) its full resolution? Can I tweak a setting to do this? Do I need a DVI-D single link? Is it impossible with DVI-D and my weak graphics card? :confused:

02-24-2009, 07:32 PM
My initial hunch was correct. The only reason I couldn't put my monitor to its full resolution was because the DVI-D dual link took too much graphics power to render a larger screen size. I bought a DVI-D single link and tried it and it worked perfectly. So my lesson from all this is: don't buy a DVI-D dual link unless you need it and you know your graphics hardware can support the much greater load.

And for some fuzzy math to support my theory, the highest setting I could do well with DVI-D dual link was 1024 x 768 x 32 x 2(for dual link) = 50,331,648. A setting I couldn't quite do well (just beyond my graphics card's ability) was 1280 x 720 x 32 x 2 (dual link) = 58,982,400. By comparison with the single link I can do 1680 x 1050 x 32 x 1 (single link) = 56,448,000. Notice that the numbers indicate that the load from my single link full-resolution setup are in about the same range as my max with the DVI-D dual link? If the numbers are an indicator, that would mean I'm pushing my graphics card to its limits to do the full 1680 x 1050 x 32 x 1, but at least it works, and I can finally use my monitor to its full potential.