Reactivity tests
Initially, we wanted to physically measure afterglow with an oscilloscope. We approached an electronics specialist, Tektronics, and they were nice enough to supply us with a sensor + oscilloscope combo of their making. This was to be used to measure the transition from white to light gray, white to a darker gray, gray to black, etc. We came up with some great 3D graphs but the problem was that practical tests (based on a visual evaluation) didn’t always match these results. A screen that was judged more reactive with the oscilloscope sometimes appeared to our eyes as being slower than other products. We therefore abandoned this method to come back to more practical, concrete, and in our opinion, realistic tests.
Our other method in place since 2005 and based on photos, has proven to be more reliable and it’s rare that these test results are deceiving. Either way, when this is the case we tell you.
Here’s the concept in this test: A car moves from right to left at high speed. The movement isn’t perfectly fluid and depending on its speed, the car is shown in several successive positions. When this process is sped up, the car goes very fast, positions are very close and the eye perceives a fluid movement.
the perfect screen 
screen with a 2 afterglow imagesA monitor without ghosting effects would have previous images completely fading away when a new one appears. This is ideal, however in practice, it's often not the case as images progressively fade. Sometimes up to 5 afterglow artifacts remain on the screen representing the visible white trail behind objects.
We capture this LCD defect with a camera at a shutter speed of 1/1000 s by taking 50 pictures per test. We then can see a monitor’s ghosting effects, or the car’s position in the entire process from the moment when afterglow is at its maximum, up until when the next image is about to be created and the previous image is the least visible.
Here are the two extreme states between which each monitor’s afterglow can oscillate.
TN 2 ms : Asus PG221
TN 5 ms : Belinea 2230 S1W
TN 2 ms : Iiyama ProLite E2201W
TN 2 ms : LG Flatron L226WTQ
TN 5 ms : Nec LCD225WXM
TN 2 ms : Samsung SyncMaster 2232BW Samsung panel 
TN 2 ms : Samsung SyncMaster 2232BW CMO panel
TN 5 ms : Samsung SyncMaster 225UW
TN 2 ms : Samsung SyncMaster 226CW
TN 5 ms : ViewSonic VX2255wmbBeyond these images, do we really see a difference between a good 2 ms and a 5 ms ? Yes. If you put the screens in clone mode, you will notice half the amount of afterglow on the 2 ms. Is this true for all 2 ms monitors? No. The 226CW failed this test and it’s no better than a 5 ms. We confirmed this on a first model provided by Samsung and then on a second which was loaned to us for verification. In fact, activation of the overdrive doesn’t change anything, or at any rate, we don’t have the reactivity of the other 2 ms monitors.
As for the other 2 ms screens, they are all pretty much equivalent. In this test, it was difficult to give an advantage to Asus, Iiyama, and LG despite the panels of various origins.
In the same way, the 5 ms screens were identical in reactivity.
One detail that stood out was that if you compare the worst 2 ms image and the best 5 ms, they are equivalent.
Now if we combine the results from this page with those of the previous test:
only one screen is very reactive in addition to having a small input lag, the Iiyama ProLite E2201W.
All the other 2 ms monitors have more than a 2 image delay.
As for the two 2232BW, we had two main observations:
1 – Reactivity was strictly identical for both models. This differs greatly from what we obtained with the various versions of the 226BW. The 2232BW-CMO no longer has an overdrive problem and is devoid of black afterglow behind objects in movement. Previously, this characteristic even pushed some users to turn off the RTA function (overdrive), meaning that they preferred 5 ms reactivity to this defect.
2 – Samsung had to make a sacrifice for the above remedy and it meant decreasing the strength of the overdrive which in turn also decreases its efficiency. This is noticeable in some of the test photos and also is clearly visible with the naked eye. And for us, seasoned monitor testers, we even noted that this screen’s reactivity was slightly below that of a classic 2 ms while a bit better than 5 ms TNs. In fact, the 2232BWs is halfway in between.
