AOC Envision G19LWK review: input lag and upscaling tested using the piLagTesterPRO

This TN 1440x900 LCD sold thru 2008.  But as it turns out it has very low lag and pretty good response time, showing that display technology has not advanced anything like CPUs or GPUs over the same timespan.  

Overview/Image quality

At native resolution viewed from straight on this LCD looks fine. Because it's a TN display viewing angles are poor when viewed from below, but are fine from the side or above. At native resolution it's pixel perfect, with zero cropping or aliasing, as you'd expect for a desktop monitor.  

For 480p/i it is mildly blurry but with very mild aliasing. Given that 480p/i was meant to display on a CRT the amount of blur is probably ideal. You can't set the aspect ratio to 4:3, so the aspect ratio is wrong, though. 

720p is also mildly bury, but has much more aliasing. It's ok at best. 

Although it's a desktop oriented display it does support interlaced modes and will track pretty much any resolution handed it so long as the refresh rate is 75 or lower. Deinterlacing is done by the BOB method.

It accepts VGA and DVI input. Because my tests device only outputs HDMI I used an adapter to plug into DVI but it didn't seem to hurt the image quality at all. VGA input has the same timing as the DVI port.

Input Lag

This display does not have a game mode, and other than colors it doesn't really have any settings. No display setting changed lag. 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.

It supports both 60hz and 75hz. Except where noted below I used 60hz.

Full Test Results 

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 it's final brightness. This combines both input lag and response time, and is closer to what you would actually experience in a game.

	Top		Bottom
Resolution	1st response	full response	1st response	full response	scan out	response time
480i	5.0	23.5	20.2	39.5	15.2	18.5
480p	4.3	22.6	19.4	38.7	15.1	18.3
720p	3.1	21.1	19.0	38.4	15.9	18.0
1080p	3.2	21.8	18.7	37.8	15.5	18.6
1440x900p @75	2.8	17.8	15.4	30.4	12.6	15.0

The input lag is excellent, as is often seen for TN panels, even ancient ones like this, ranging from 2.8 to 5ms. The response time was about 18ms for TV modes, but was a bit lower for native resolution,  around15ms. This difference was repeatable but somewhat hard to explain. Normally differences in RT have to do with the reduced brightness range used in TV modes, but this LCD has the same RT no matter what the brightness transition. So maybe there's a different circuit that handles native resolution. 

You'll notice that interlaced and progressive modes have nearly the same lag. That's because this display has built in bob deinterlacing, which causes a decent amount of flicker but no lag. I didn't see any afterimages develop from the flicker, and I wouldn't expect it to, but I only ran it that way for a few minutes. 

The final thing to notice is that the full response at the bottom of the screen is about 3ms faster in 75hz mode than 60hz. This means the LCD really can refresh at 75hz, as reflected in the significantly faster scan out time in 75hz mode. Some displays are advertised as 75hz compatible but actually draw at 60hz and drop frames in order to keep up. Another win for a very old LCD. 12

Results compared to other displays

To allow quick comparison between many display I've summarized the results across all the displays I've personally tested with the piLagTester Pro. Min lag is the first response at the top of the screen, real lag is the full response at the bottom. The list is sorted by real lag in native mode, so this display gets a boost from support 75hz. 

		all values are in ms
Display	Year made (TV?)	Native Res	native min lag	native real lag	480i real lag	480p real lag	720p real lag	1080p real lag	native response time	native scan out
Dell E198FPb	2008	1024p	2.7	20.4		39.0	35.0		5.00	12.70
Vizio VO370M	2010	1080p	2.5	23.6	83.0	49.0	47.0	24.3	5.47	15.67
Dell U2410 (game)	2010	1080p	4.0	26.2	62.2	28.3	26.5	26.5	6.00	16.20
AOC/Envision G19LWK	2010	900p	3.1	31.2	39.5	38.7	38.4	37.8	15.50	12.60
Dell E2211H	2014	1080p	3.0	33.6	34.7	34.5	34.1	33.8	15.00	15.57
Panasonic TH-58PE75U	2008	720p	28.0	34.0	34.0	34.0	34.0	34.0	6.00	0.00
Dell 1907FPc	2008	1024p	3.0	34.0		35.9	34.8		15.00	16.00
Corprit D157 (hdmi)	2021	1080p	3.1	34.5	34.9	34.8	34.6	33.9	16.25	15.13
Samsung S27C230	2014	1080p	2.9	36.1		36.6	36.1	37.0	18.25	14.97
Vizio E470VL (vga)	2011	1080p	22.0	39.0		39.0	39.0	39.0	9.00	8.00
Dell U2410 (sRGB)	2010	1080p	20.5	42.8	62.4	45.0	43.1	43.1	6.13	16.13
RCA L40FHD41	2010	1080p	20.3	46.6	65.0	48.0	47.0	46.0	9.68	16.63
Sony 40VL130 (game)	2008	1080p	22.8	47.3	66.3	49.0	47.3	47.3	9.08	15.43
Polaroid FLM-373B	2007	720p	28.0	49.0	82.0	49.0	49.0	49.0	7.00	14.00
Philips 42PFL3603D/F7	2009	1080p	29.0	50.0	84.0	50.0	50.0	50.0	5.00	16.00
Emprex HD 3202	2007	720p	27.0	50.5	126.0	51.0	50.0		8.50	15.00
LG 42LC2D	2006	720p	28.3	50.6	54.6	50.8	50.4		6.30	15.95
GPX TDE3245W	2016	720p	28.0	51.0	102.0	51.0	51.0	51.0	8.00	15.00
Sony KDL-46EX400	2010	1080p	28.0	52.0	87.0	52.0	52.0	52.0	8.00	16.00
Toshiba 40L2200U	2014	1080p	30.0	56.0	74.0	56.0	56.0	56.0	10.00	16.00
Vizio VO22L FHDTV10A	2008	720p	28.0	61.0	94.0	61.0	61.0	61.0	18.00	15.00
Sharp LC-C3234U	2009	720p	33.0	64.6	83.6	66.6	64.6		15.00	16.60
Toshiba 46L5200U	2013	1080p	55.0	71.0	89.0	76.0	71.0	74.0	8.00	8.00
Sony 40S20L1	2007	720p	48.4	72.0	90.1	72.9	73.4		9.60	14.00
Samsung HP-T4254	2011	1080p	69.7	75.7	94.1	76.0	75.7		5.00	1.00
LG 47LW6500-UA	2012	1080p	66.6	80.7	149.7	149.0	81.7	80.9	2.27	11.83
Vizio E470VL (hdmi)	2011	1080p	69.0	86.0	128.0	95.0	95.0	86.0	9.00	8.00

Response time is a bit slow, but the sum is still very competitive. Despite the age it's still one the fastest displays I've tested.  It seems that TN displays have had low lag for a long time. On the other hand, the long response time means that motion will be a little blurry so it's definitely not an ideal gaming monitor. But heck it's not bad, at this price range especially. 

Conclusion

I strongly prefer IPS panels for their accurate color over wide viewing angles. A good IPS display will cost more than a TN display, but will almost certainly be slower. If you are primarily concerned with gaming TN might be the way to go, though of course not every TN display is optimized for low lag and fast response.

Other models

I tested the AOC Envision G19LWK model, which is the 19" version. There appears to be two versions of this panel: the G19LWK and the G22LWK.  Based similarities in their names, specs and release date I suspect that they would perform similarly, though the G22LWK is higher resolution. Honestly, the TN displays from this era that I've tested all perform quite similarly; probably any TN model would be about the same league, at least in terms of lag. I have noticed that many do not support interlaced modes however so if you interests are retro you might need to be more choosy.