ah ty. this review I was reading of a monitor said that displayport or dual link DVI was the only way to get 120hz. it didn't mention 1.4 hdmi at all. Plus I didn't know if there is a difference between 1.4 and 1.4a hdmi.
From Wikipedia (Not always the most reliable source of info):
HDMI 1.4a was released on March 4, 2010 and adds two additional mandatory 3D formats for broadcast content, which was deferred with HDMI 1.4 in order to see the direction of the 3D broadcast market.[121][122] HDMI 1.4a has defined mandatory 3D formats for broadcast, game, and movie content.[121] HDMI 1.4a requires that 3D displays support the frame packing 3D format at either 720p50 and 1080p24 or 720p60 and 1080p24, side-by-side horizontal at either 1080i50 or 1080i60, and top-and-bottom at either 720p50 and 1080p24 or 720p60 and 1080p24.[122]
Ok so it looks like I lied to you... Looks like computer monitors use a Dual-link DVI cable to do 120hz.
Per a comment on newegg (and some research on my part):
"This TV can not do PC 120hz, as it needs a Dual Link DVI or DisplayPort 1.2 input in order to do so. Only those 2 interfaces have enough bandwidth as of today to handle all the throughput required for 120hz @1080p. If the technology for real PC 240hz ever comes along, keep in mind that ONLY DisplayPort 1.2 is capable of doing 240hz @1080p.
Preferrably the 120hz monitor you buy should have DisplayPort inputs, as those are the simplest to use and allow you to do Eyefinity in the future without $100 adapters for the third monitor. Samsung is soon releasing 27" 120hz monitors with DisplayPort inputs, models SA750 and SA950 (not the TA7/950, those are TVs), wait for those.
So basically:
for REAL 120hz (@1080p) it needs a Dual Link DVI or DP 1.2 input.
for REAL 240hz (@1080p) it would need a DP 1.2 input.
All sets without these inputs are image processing or proprietary poop, not the real deal."