Bad DVI Cable Causes Red Dots

I’d been having a chronic problem of shimmering red dots appearing on my LCD screen every time I tried to use a DVI cable instead of a VGA cable.  The dots appear around areas of high contrast like the border between a window and the background or even in the wallpaper itself.

I had previously tried many different graphics cards and a new power supply and finally came to the conclusion that it must have been something to do with my motherboard since my wife’s computer with nearly the same monitor didn’t have the same problem.  It really didn’t occur to me that it could be the cable.

So what’s wrong with using the VGA cable, well for one I was losing a few lines of my desktop on the top edge of the monitor, you’d think that the resolution would be 1:1, but evidently something is lost in the digital to analog to digital conversion.  I could live with it, but it constantly annoyed me every time I noticed the tops of windows being cropped.

A few days ago I was particularly annoyed, so I did some more research and I found a few other possible causes besides overheating graphics cards and bad power supplies.  There were posts about some bad nVidia graphics card drivers, but I wasn’t running  the specified version.   So on a whim I took the DVI cable from my wife’s computer and replaced mine.  What do you know, it worked.

Until now I didn’t think that the quality of the DVI cable mattered.  It’s a digital signal so unless the cable is very long one cable shouldn’t be any better than another.   Evidently I was wrong.    I purchased a cheap DVI-I single link cable from Best buy and now my display runs just fine over DVI.