This might have already been pointed out in this thread but it bears repeating pixel response time means very little, any more its simply a marketing term there is no industry standard for measuring grey to grey response time. a better measure is the ISO standard, black to white. TN panels have been stuck at 8 to 5 ms, VA panels around 12 and IPS panels around 12. unfortunately when was the last time you played a game where there is a quick succession of black and white frames?
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This is a graph of what actual response times look like on a TN panel, this monitor would probably be quoted at 10ms
before overdrive
and that brings me to overdrive. Overdrive brings G2G into the picture
this technology is based on applying an over-voltage to the liquid crystals to motivate them into their orientation faster. This process forces them to a full white (inactive) to black (active) transition first. The crystals can then drop back down to the required intermediate grey level. This is helpful as the rise time of a liquid crystal was always the slowest part (response time = Tr + Tf). This technology does not help improve the ISO black > white transition much since that already received the maximum voltage anyway, but transitions from grey > grey are significantly reduced. The improvements in grey transitions however are helpful in producing a faster panel overall as these changes have always been slower colour changes in TFT panels and it is important that the response time is low across the whole range of transitions (0 – 255). Screens featuring RTC will normally show an improved responsiveness in practice and reduced motion blur and trailing. Manufacturers will usually quote a "grey to grey" (G2G) response time figure on screens using this technology since they are normally the fastest transitions available. Look out for "G2G" quoted in the spec sheets.
of course this is a double bladed knife properly done overdrive works GREAT at reducing ghosting and blur, but poorly done overdrive add more pain then it solves
Example
good overdrive
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as you can see there are no artifacts around the car or speech bubble infact it looks as if its standing still, also note that this is a 120Hz TN Samsung
VERY BADLY DONE OVERDRIVE
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as you can see there are black artifacts almost 3 frames deep. this is a 60Hz TN BenQ
ALL QUOTES AND IMAGES TAKEN FROM
http://www.tftcentral.co.uk