2405fpw LCD vs. CRT - 40ms signal delay / latency for LCD users ?!?

larkin said:
That's just false. My monitor and case were the last items i purchased because it took the longest to research (about 4 months). I read the internal specs documents for monitors and learned how the measurements are taken. The old way of measuring is white to black to white, otherwise knows as "rise and fall time" or Tr+Tf. Your dell monitor, just like samsung and about everyone else in the industry measures their responce time as the average grey-to-grey. The dell is rated at 16ms, from dell's website "Pixel Response Time (Gray to Gray): 16 milliseconds". I spent about 2 hours on the phone with samsung to find the actuall rise and fall responce time and the actuall grey-to-grey responce. I had to get transfered to senior 3rd teir tech staff who talked with the korean manufacturers and then called me back with the info the next day. The rise and fall number is 12ms, which is better than the dell's 'filthy and disgusting grey-to-grey marketing' number of 16ms. Your dell rise and fall is probabbly around 30ms if you want to play uber speculator game.


My mistake. I obviously should have researched more before posting. Someone I know who claims to be an authority on the subject blamed the substitution of grey to grey instead of white to black to white on samsung.

*Need to not take people for their word and do some research myself*
 
Out of curiosity I ran a dual monitor test using two CRTs, The results show that there is absolutely no lag when running dual CRTs, so that eliminates the possibility of dual the monitor mode itself / videocard etc. causing the lag.


The CRTs used in the test were a 24" Sony FW900 and a 17" KDS ,both running 1024x768 @ 85hz via 7800 GTX 512mb card, This card has no vga outputs so I used DVI to VGA adapters on both monitors.

Heres the pics ,they're a bit fuzzy due to very fast shutter speed & max ISO settings on my digicam, The numbers were being generated so fast in the test (AMD X2 4800+) that I had to use these settings to avoid a blurry shot.

Monitors used in test (pic)
And the Result
 
Zarathustra[H] said:
My mistake. I obviously should have researched more before posting. Someone I know who claims to be an authority on the subject blamed the substitution of grey to grey instead of white to black to white on samsung.

*Need to not take people for their word and do some research myself*

You were almost right. The 2405fpw is 16ms BtW (Tr=8/Tf8), 12 ms G2G. What some (samsung *cough* have done is to report only Tr earlier without the Tf and listed their panel as 8ms). The Dells listing is based upon Samsungs reports of the panel, since its a Samsung PVA panel that is used... I remember that several people claimed that the Dell have to be 8ms since it uses the same panel as the Samsung (and they linked to the panel specs of the samsung semiconductor) :p
Here is another discussion about the 242mp which uses the same panel as the 2405fpw (LM240M1) link where Samsung have claimed 8 ms on the same panel...

The Samsung 243T is also listed with BtW. Samsungs own testing of this panel is shown here (datasheet pdf: link

I wonder what BtW timings Samsung sold their panels with... ;) (did someone say 25ms BtW? But the datasheet says Tr=17 and Tf=13 (30ms)... someone bad in math?) :p

Here is a little reading about Btw vs GtG:
Response time is defined as the time required for an LCD pixel to change from fully active (black) to fully inactive (white), then back to fully active again. Many manufacturers, on the other hand, report their LCDs' gray-to-gray response times. Pixels are rarely completely on or off--instead they cycle between gray states, that is colors--and, in general, switching between gray states is much slower than switching between black and white. However, some also argue that measuring gray-to-gray response time is pointless, since the manufacturers rarely tell where in the cycle they start and end their measurements. To alleviate this confusion, the Video Electronics Standards Association (VESA) plans to introduce a spec standardizing response time measurement sometime in 2006.
link

A little sidenote about specs and samsung panels... For all of those who thought they got a screen with 1000:1 typical contrast and 500 typical brightness got screwed as well. The samsung panel of the 2405fpw, LTM240M1 are actually 700:1 and 400 link. Extremetech measured the contrast of the 2405fpw at 600-700 typical which is great, but not what you bought... :p
 
I just bought an Acer AL2416W-SD LCD. It's a twenty-four inch widescreen and I came straight here searching for keywords "LCD DVI LAG".

It's very obvious that there is significant lag here. I could estimate a good 1/20s of lag just by moving my mouse pointer around on the desktop. I can actually flick the mouse quickly and watch the mouse pointer move exactly as I flicked my wrist after I've physically stopped moving. It's really bad and makes playing realtime games extremely frustrating. I'm a big fan of racing simulators so you could imaging just how uncool this lag is.

And unfortunately for me returning this monitor for this reason may be difficult... does anyone have any information regarding the way the DVI signal is processed before actually displayed on the LCD? I'd like to atleast know why exactly this is happening rather than read about a bunch of [H]ardforumers bicker that the the problem doesn't exist.
 
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