ULMB and LightBoost have different overdrive adjustments, and dynamic ranges (compressed color range) to assist in speeding up LCD pixel transitions differently for different needs.masterotaku wrote:Lightboost is specifically made for 3D, so it makes sense (what doesn't make sense is not using that overdrive setting for ULMB). With some tweaks it's possible to use ULMB in 3D instead of Lightboost. The 3D crosstalk in ULMB is a quite a lot worse. Little overdrive differences in 2D can make great differences in 3D. It's still fun to use with very low custom refresh rates, for testing.Vega wrote:My biggest takeaway though is for some reason Lightboost has less strobe-cross talk. Not sure why, if it has to do with the overdrive settings etc..
LightBoost: More aggressive, dynamic range sometimes reduced, creating worse contrast ratio in exchange for less strobe crosstalk -- very important for 3D glasses
poor contrast, usually brighter blacks -- but less strobe crosstalk
ULMB: Less aggressive (more strobe crosstalk) but preserves full dynamic range of unstrobed (more coloreful)
better contrast, usually dimmer blacks -- but slightly more strobe crosstalk
Sometimes the difference is so small (10-20%) that you need to use a colorimeter to realize you're comparing a 750:1 contrast ratio with 850:1 contrast ratio (for a specific screen). Sometimes it is so tiny that it's within the noisefloor of a colorimeter, (e.g. if LightBoost is essentially compressing the dynamic range by only, say, 5%) -- this helps ensure undershoot/overshoot room beyond the dynamic range for easier overdrive compensation (without using voltages beyond spec of an LCD panel).
Programmer/Engineer/Technical Info: To quickly overdrive a pixel from RGB(255,255,255) to RGB(3,3,3), the pixel might slam against the black floor RGB(0,0,0) and get stuck there without rebounding to RGB(3,3,3) quickly -- or trying to voltage it as RGB(0,0,0) (very small difference to RGB(3,3,3)) means you don't transition the pixel nearly as fast. Overdrive overshoot issue amplifying visibility of unwanted ghosting or strobe crosstalk because pixel can't rebound as fast because it slammed at the end of the color range. Now, if you compress dynamic range where you're using, say, RGB(10,10,10) through RGB(240,240,240) of a panel, then the equivalent of RGB(3,3,3) may be RGB(12,12,12) instead. Now you've got 12 clicks of overdrive overshoot room below, rather than just 3 clicks of overshoot. You can even briefly voltage (overdrive) at RGB(0,0,0) to accelerate the movement from RGB(240,240,240) to RGB(12,12,12) and it'll hit nearer that target color without either slamming against the floor/ceiling nor having too little voltage differentials in the overdrive room below black / above white. More accurate GtG is thus achieved by a narrower dynamic range -- meaning you get lower strobe crosstalk during reduced contrast. You can achieve something roughly similar to LightBoost when doing with ULMB by adjusting black level brighter and white level dimmer (via contrast/brightness adjustments, even via NVIDIA Control Panel) -- the strobe crosstalk goes down quite a bit when you digitally adjust to brighter blacks & dimmer whites during ULMB -- but your contrast ratio gets bad / more washed out...