I recently got a 120hz monitor and learned the hard way, like most people, that HDMI 1.4 doesn't support 120hz in 2d or 60hz in 3d. There's no DVI out on my M18x, so I did some research, and learned that the displayport is capable of 120hz. As luck would have it, there's no displayport on the monitor, so I ordered this dp to dvi converter (http://www.amazon.com/gp/product/B004I6L6DW/ref=oh_o06_...). Based on the first review, which as (actual) luck would have it said that it solved the problem, specifically with the alienware M18x. However I'm still only getting the option for 60 hz in the Nvidia control panel. The Windows display panel lists 120hz as an option, but doesn't seem to work. It just flashes back to the desktop after a while.
It's worth noting that in advanced settings in Windows display options, under "monitor", nothing is listed. There are 2 blank selections I can make. But I assume this is because Nvidia's control panel has 1st priority on being in control of such stuff. Nvidia's control panel DOES seem to identify the monitor as an Asus278, but isn't giving me a 120hz option.
Active conversion allows full dual-link DVI resolution (2560x1600)
USB-Powered operation means no wall outlet or bulky external power adapter is required
Maximum resolution up to 2560x1600 with DVI Dual-Link
Supports 1920x1080 with Single-Link displays
Support for any DVI-D display, including televisions and Apple Cinema Display HD
it only supports single-link displays so no 120hz.
Scratch everything, I figured it out! There was a custom option I wasn't seeing in Nvidia control panel, and all is well! I feel stupid for not seeing it before, but I'm uber-relieved. Thanks for your input Ricardo, I'm gonna go spoil myself with silky 120 hz and make it so 60fps is never good enough again :-p