Dell E228WFP review: input lag and response time tested using the piLagTesterPRO
Image quality
The set has no options to adjust cropping/scaling. There is mild aliasing outside the native resolution and no way to adjust the aspect ratio.
Because it is a TN display, the viewing angles are more limited than for most TVs or any IPS display
The display has VGA and DVI inputs. I tested DVI using a passive HDMI adapter.
Input Lag Results
I used a piLagTesterPRO to measure input lag. This device sends a frame of video over HDMI and measures how long it takes to display it. This display does not have a game mode.
I report two kinds of values. 1st response measures how long it takes for the TV to start responding (I use a 5% change in display brightness). This overly optimistic value doesn't tell how long it takes to see anything useful, but matches what other reviewers call input lag. full response is a more realistic measure of lag, and requires the display to reach 80% of full brightness. This combines both input lag and response time, and is closer to what you would actually experience in a game.
The recommended resolution and refresh rate for this display is 1680x1050x60, but it also supports 75hz at slightly lower resolutions just as well, properly syncing with the vertical refresh to produce constant, steady input lag. Looking at the data at the bottom of the screen, you can see faster refresh rates really do help overall lag, reducing it by about 3ms in total. Unfortunately the lower resolutions do suffer a bit from aliasing, but in a FPS or any 3D twitch game I doubt you'd notice. It's interesting that the panel is able to do 75hz no problem, but the rendering unit can't keep up with that data rate (pixel clock) at native resolution. It's so close, with 75hz working at 1440x900 and 1400x1050. Makes you wish Dell had splurged just a tiny bit more on the rendering unit, making this a true 75hz display.
I also tried some unlisted 80hz modes but the monitor refused to sync to them.
It cannot handle an interlaced signal in any mode, and it can't downscale from 1080p, but it seems to be fine upscaling from any resolution below 1680x1050.
Response time was about 5ms. It's fairly independent of the amount change between frames, but does have a overdrive artifact where it moves very quickly to about 70% of the final brightness, pauses a frame, and then jumps the rest of the way. I choose to set the response time as the point when it finished that first step, otherwise the value would be more like 20ms(!). From a lag perspective, that first step is a valid place to measure, as you can clearly see that level of brightness, but from a motion clarity perspective the 2nd value has more validity.
Results compared to other displays
To allow quick comparison between many displays I've summarized the results across all the displays I've personally tested with the piLagTester Pro. Min lag is the time to the first response, measured where the screen starts drawing (typically, the top); real lag is the time to the full response, measured where drawing finishes (usually the screen bottom), i.e. input lag + scan out + response time. Numbers in red denote average values that can vary by up to 8ms between power cycles.
This list is sorted by real lag for each display's native resolution and max refresh rate. Since this display can only do 60hz at native resolution it doesn't get any boost in this ranking from the fact that it can also do 75hz at lower resolutions.
This monitor is very high on the list, as would be expected by the fact that it's a TN computer monitor. In fact, if we had used the performance from a 75hz mode it would be tied for the fastest monitor I've ever tested. That is largely due to its very fast response time of 5ms. Keep in mind, however, that this monitor has a two-step response time curve, and if you used the 2nd final step as the measure it would be closer to 20ms, which would make it one of the slowest pc monitors (but still way faster than most TVs). As to which is more fair, I don't know. It certainly responded very fast in that first step, but the slower second step does mean moving stimuli are less clear.
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