[geeks] LCD display options

[Nathan Raymond]

On Thu, 24 Feb 2005, Joshua Boyd wrote:

> Personally, I wouldn't buy a display that had a response time more than
> 16ms for normal computers.  The issue here is that typically you can't
> set the graphics card's refresh rate below 60hz, and 16ms is the
> response time needed for 60hz display.  20ms would be fine for a 50hz
> display, but if the computer won't let you go that low, then you WILL
> have the stereotypical LCD display blurriness on motion.

Unfortunately, it's not as simple as picking a response time faster than 
16ms.  Here's why:

http://graphics.tomshardware.com/display/20050215/lcd-04.html

> Again we'll recall our test method: the curve shows the different 
> latency values for various levels of gray. A black-white alternation is 
> shown on the curve by a point at X-axis 255, a black-gray alternation 
> produces a point at X-axis 125, a black-gray alternation shows as 50, 
> etc.
> 
> The official ISO latency rating specified by the manufacturer is only 
> for black/white transitions (0/255). While the value we measured agrees 
> with the manufacturer on this point, it's not of much value in judging 
> the actual responsiveness of the panel in practice.
> 
> As you can see, the curve didn't quite reach the 8 ms we were promised, 
> but an explanation is in order. With the monitor pushed all the way to 
> 100% contrast, we did get roughly 8ms at the ISO point (255 on the 
> curve). The only problem is that the image is not usable; the color 
> dynamics are completely wiped out. So we chose a more appropriate 
> contrast adjustment, one that's closer to the actual conditions under 
> which the display will be used. And that resulted in a latency reading 
> of 10 ms in the best case.
> 
> Does that mean that this is a bad monitor? By no means. As the curve 
> shows, the worst latency measurement we got on this Samsung 190EX-L01 
> panel was 27.5ms, whereas 12 ms models easily go beyond 30 and even up 
> to 35ms. And we've found 12 ms models sufficiently responsive for gaming 
> use. So the L90D+ is a notch even above that, and we noticed no 
> objectionable remanence, even with the fastest games. While the 12ms 19" 
> models were a little slower than their 17" counterparts, the 8ms 19" 
> panels can rival the fastest 17" units. Hyundai has produced a unit with 
> both a generous display area and fast response.
> 
> We don't need to repeat it again: don't trust manufacturers' claims 
> about response characteristics. Still, most people might be surprised to 
> see a monitor that tests nearly 300% above its specifications (27ms 
> instead of 8). With LCD monitors, this is par for the course. (If you 
> remember, the first LCD monitors that went on sale specified a refresh 
> rate of 60Hz AND a latency of 30ms, whereas 16ms (1/60 Hz) is the 
> minimum for delivering that refresh rate. So with that in mind, we 
> should expect nearly anything...)

- Nate