The ViewSonic VX2268WM says it displays 1680x1050 @ 120hz, but it only has one DVI port, I've heard that one DVI port doesn't have enough bandwidth to display at 120hz in that high of a resolution. How could this monitor possibly receive 1680x1050 @ 120hz with only one DVI port?
1920x1200 @ 60Hz x 24 bits per pixel = 3.317 Gb/sec
I'll show my work:
1920x1200 = 2,304,000 pixels
2,304,000 x 60 = 138,240,000 pixels per second
138,240,000 x 24 = 3,317,760,000 bits per second, or 3.317 Gb/sec
Single-link DVI maximum speed: 3.96 Gbit/s
As you can see, 1920x1200 at 60Hz is near the limit of single-link DVI, which is why you need to go dual-link DVI to do 2560x1600.
1680x1050 @ 120Hz x 24 bits per pixel = 5.08 Gb/sec
This is why the Samsung 2232rz and Viewsonic 2265wm require dual-link DVI.
1920x1200 @ 120Hz x 24 bits per pixel = 6.63 Gb/sec
Dual-link DVI maximum speed = 7.92 Gbit/s
So, 120Hz 1920x1200 could be done on dual-link DVI.
2560x1600 @ 60Hz x 24 bits per pixel = 5.90 Gb/sec
Falls about midway between 120Hz 1680x1050 and 120Hz 1920x1200.
"Dual Link DVI" doesn't mean you have 2 DVI cables, it just means a single cable capable of supporting twice the standard DVI-D bandwidth. I think the dual link cables have one of the flat connectors rotated 90 degrees where it goes in the cross shaped slot but are otherwise physically identical to the single link cables. I have the same screen and 120hz works fine with the dual link DVI cable that came with the monitor.
^^nope it just has all the pins, in the middle as well, most available dvi cables have been dual link for years already. The 'cross' or the bar(s) at the other end is ground for the analog R,G and B signals.
and also "Dual link maximum data rate is limited only by the bandwidth limits of the copper the DVI cable is constructed of and by the DVI signal's source." So it isn't just twice the bandwidth of a single link, it can be much more if used equipment allows... http://en.wikipedia.org/wiki/Digital_Visual_Interface