As far as vendors' specifications about LCD panel latency go, we've heard it all - claims of 25 ms that tested out to 130 ms; a manufacturer's latency value claim of 8 ms that only did just better than 25 ms; 12 ms panels that are less responsive than 20 ms ones and so on. So understandably, we've learned to mistrust manufacturer specifications, to the point that we now check the actual latency of LCD monitors ourselves. For a detailed look at how we test latency, see LCD's 17" and Larger Reviewed .

So when vendors introduced at CeBIT this year Gray to Gray (GTG), a new calculation formula that they said would meet the measurement demands of next-generation panels and replace the black-to-white calculation formula, we were skeptical. Our suspicions were compounded by the vendors' tech representatives who remained vague when asked to explain the new formula.

But the new panels are here and since we measure latency ourselves - GTG or no GTG -the method the manufacturers use doesn't make much difference to us.

Added to the new formula calculation is ViewSonic's Overdrive technology, which in the panel we tested offers what the vendor says is a GTG latency value of 8 ms. So we thought we would do a comparison of a ViewSonic TN vs. a ViewSonic Overdrive panel, to see if the new technology and measurement calculation were really worth their salt.

Why did we choose a ViewSonic LCD for the test? First, because it's the first product to offer GTG latency calculations in a consumer monitor. Then because the two units we tested, the VP192s and the VP191b, use the same plastic shell, the only difference being the choice of the LCD panel.