DVI-I - Single Link vs Dual Link

Solution 1:

Single-link and Dual-link only apply to the digital connection, not the analog VGA connector. See the DVI to VGA pin conversion.

There shouldn't be any difference between the adapters. I don't know why one has all the pins in it when it doesn't need them.

Solution 2:

I have done a bit more searching and I came across this:

DVI dual link as the name implies has more conductors than the DVI single link for transmitting signal. Single link DVI supports a maximum bandwidth of 165 MHz (1920 x 1080 at 60 Hz, 1280 x 1024 at 85 Hz) and utilizes 12 of the 24 available pins. Dual link DVI utilizes all 24 available pins and supports 2x 165 MHz maximum bandwidth (2048 x 1536 at 60 Hz, 1920 x 1080 at 85 Hz).