If you've been shopping for an LCD TV, you've no doubt noticed that manufacturers are touting models with higher and higher "refresh rates," such as 120 Hz and 240 Hz. Unless you are a confirmed videophile, you've also probably scratched your head and said, "that's nice; what does it mean to me?"
Refresh rate refers to how often a TV image is repainted on the screen. Up to now, most TVs used a refresh rate of 60 Hz, which means the image is repainted on the screen 60 times per second. That's fast enough so that the eye perceives what it sees as one fluid, moving image rather than a string of individual frames. Boosting up the refresh rate to 120 Hz or 240 Hz updates the image two times or four times more often than with a 60 Hz refresh rate.
So, then, what's the advantage of doing that? If you are talking about plasma TV, the answer is not much. However, LCD TVs have traditionally been criticized for being prone to motion blur, which is caused by LCD's slower natural response time compared to plasma. The thought behind faster refresh rates is that forcing the screen to update more often overrides the slower response times, wiping out motion blur in the process.
Whether or not a faster refresh rate actually makes a noticeable difference in reducing motion blur is a matter of some debate, however. Faster refresh rates do appear to sharpen up test patterns and certain types of motion, such as fast moving text on a crawler. However, most experts, such as CNET's David Carnoy, don't see that much of a benefit when it comes to typical TV images. For one thing, LCD response times have improved to the point where motion blur has been greatly reduced; certainly the ghostly comet tails that plagued some programming, such as sports, are mostly a thing of the past.
Instead, in the opinion of many experts, most motion blur seen by viewers today is more likely in the source than caused by your TV. Others, however, claim that it really makes a difference in their eyes. If you are considering spending more money for a TV with a 120 Hz or 240 Hz refresh rate, I recommend spending some time auditioning TVs in the store to see if you can detect any difference for yourself.
See our full report for information about the latest LCD TVs -- with and without 120 Hz and 240 Hz refresh rates.