Let's Talk Panel Technologies

We've already given a brief rundown of TN panels and what they offer, but let's expand that to include the other three panel technologies. Here's the breakdown:

LCD Panel Technology Comparison
Panel Type IPS MVA PVA TN
Viewing Angles Excellent Excellent Excellent Okay Horizontal; Poor Vertical
Color Quality Usually Excellent Good to Very Good Usually Excellent Usually Good
Contrast Ratio >500:1 >500:1 >500:1 Usually >500:1
Color Gamut Depends on Backlight Depends on Backlight Depends on Backlight Depends on Backlight
Processing Lag 0ms (Usually?) 0-3ms 17-50ms 0-2ms
Response Time 6ms GTG 6ms GTG 6ms GTG Typically 2ms GTG
Cost Very High Very High? High to Very High Low to Medium

There are many similarities between IPS, MVA, and PVA - and note that these are now usually "Super" IPS/PVA or "Advanced" MVA. There are a few variants within the base panel type (i.e. E-IPS, H-IPS, and S-IPS), but the patterns generally remain true. Even TN panels have several areas that often overlap with the other techs. Let's look at the various areas in detail.

Starting with contrast ratios and color gamuts, modern LCDs have now reached the point where all panels will generally achieve a greater than 500:1 contrast ratio. Do not confuse this with "dynamic" contrast ratios, where the backlight can vary in intensity to help produce darker blacks and brighter whites at the cost of color accuracy - and it's also impossible to have bright whites and dark blacks concurrently, unless you have zoned backlighting, as current panels run the backlight at a uniform level for the entire display. Backlights also affect color gamut, with the key aspect being how much of the standard color spectrum the backlighting creates. Anything over 100% of Adobe RGB 1998 is overkill, and for most users even 82% of Adobe RGB 1998 (100% NTSC) is sufficient.

The other areas show more differentiation. Viewing angles greatly favor anything other than TN. It's worth noting that while vertical viewing angles often aren't as important as horizontal angles, if you want a display that can run in portrait mode you will definitely want to avoid TN panels (since in portrait mode the poor vertical viewing angles become horizontal angles). Manufacturers are also very generous in how they determine viewing angles, as they only require the display to maintain a 10:1 contrast ratio to qualify as "viewable". Realistically, we would say TN panels have a vertical viewing range of about 30° (15° up/down) before you notice severe image quality changes (i.e. from above the display becomes washed out, and from below it becomes very dark). Horizontal viewing angles on TN panels are probably closer to 60°, or even 90° if you're not super demanding. Compare that to the claimed 160° vertical/170° horizontal and you'll realize how inflated this spec has become with the target 10:1 contrast ration. In contrast, IPS/MVA/PVA all manage a fairly consistent 120° viewing angle in both vertical and horizontal alignments - possibly more if you don't mind the trapezoidal distortion caused by viewing from oblique angles. These displays advertise 176 or 178° viewing angles.

Color quality is also generally better on everything that's not TN, although here the (only) MVA panel we've tested seems to fall a bit short. When combined with viewing angles and the distortion that can cause to colors on TN panels, we'd stick with one of the other technologies if you want to get accurate color. In truth, this is mostly important for imaging professionals, as your eyes and brain will compensate to the point where you usually won't notice the difference. TN panels can also perform well in color accuracy, but they frequently do not because the manufacturers don't feel that's the target market - and in fact many displays have poor color accuracy by default because a lot of people prefer saturated colors. Also note that TN panels do not natively reproduce 8-bit color spectrums, relying instead on dithering and interpolation (switching rapidly between the two closest gray levels) to expand their 6-bit panels into pseudo-8-bit displays. This often shows up in color accuracy testing on TN displays with one or two colors having a high delta E while the rest are very close to ideal.

Pixel response times are another bloated statistic, with claimed response times of as low as 1ms for some TN panels and most now stating 2ms GTG (gray to gray). In theory, that would mean refresh rates of up to 500 Hz would be possible with no image persistence between frames. While no LCD currently available offers a refresh rate higher than 120Hz - and even those are relatively rare, only recently showing up with NVIDIA's 3D Vision technology - we still see image persistence on every LCD we've tested. That's not to say TN isn't a bit faster, but the difference is small enough that most users won't notice; either the response time will be "slow" on any LCD (relative to a CRT), or else it will be fast enough that you won't care.

Processing lag is potentially related to pixel response time. We don't know for sure if the lag comes after the crystal matrix receives a new voltage or if it comes before the voltage change, but we do know that of the tested panel technologies currently available, PVA seems to suffer the worst in this area by far. We only have one reference point on MVA panels, but we've read other reviews that support the idea that MVA response times are significantly better than on PVA. Processing lag can also come from hardware scalers used to support other resolutions, the prime example being Dell's 3008WFP. Even at native resolution, that display reportedly has anywhere from 10ms to 50ms of processing lag (depending on the revision that was tested). We have not seen any similar issues with other panels, most likely because scalers for lower resolutions have been around for quite a while and have been tweaked for optimal performance.

We also haven't tested any IPS panels outside of 30" LCDs, so we don't know for sure how IPS fares at other resolutions. Given 30" panels command a price premium, they may perform better overall than the smaller IPS displays; however, we believe IPS panels inherently process images as fast as any other LCD technology. Finally, it's worth noting that we have not been able to compare any LCD panel to a CRT for processing lag - we don't have access to any good CRTs anymore for comparison. Anecdotal evidence suggests that the best LCDs may still introduce a 15-30ms lag relative to a CRT. For better or worse, LCDs are here to stay and CRTs are a dying breed, so we'll constrain processing lag comparisons to LCDs and other newer panel technologies (i.e. OLED, SED, plasma, etc.)

Finally, we have to put all of this into perspective by introducing price into the equation. TN panel LCDs are by far the cheapest, often costing half as much as the same size display with an IPS/MVA/PVA panel. Since the non-TN displays do cater more towards professionals, some of the price difference may be artificial, but TN panels are still the least expensive option. They are also the oldest LCD technology, having been around since the dawn of LCDs. As much as you might want a high quality IPS display, when it comes down to a choice between a $400 22" IPS display or a $175 TN display, it's no surprise that a high percentage of people go with the inexpensive TN option.

So which panel technology is "best"? Clearly, it depends on many factors including pricing. Without price, I'd personally take an IPS display over any of the others, but again I may be biased by having only used 30" IPS panels. Many LCD HDTVs also use IPS panels, and given the recent growth in the HDTV market we'd expect there to be a few more improvements in the base technology. Like other displays, however, many HDTVs are now beginning to ship with TN panels, so if you're thinking about getting a new HDTV you'll definitely want to exercise care in what you buy.

Index A Closer Look at the BenQ FP241VW
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  • darklight0tr - Wednesday, June 17, 2009 - link

    Agreed. I've owned the DELL 2707WFP and recently upgraded to the 2709W and never experienced any lag with either one. I guess it just depends on the user. Reply
  • Lucfx - Wednesday, June 17, 2009 - link

    FYI
    One of the best displays I have ever seen (and cheap, too):
    http://www.lge.com/products/model/detail/w2600hp.j...">http://www.lge.com/products/model/detail/w2600hp.j...

    Stop buying garbage, buy this one. I have it, I love it.
    Reply
  • darklight0tr - Wednesday, June 17, 2009 - link

    Unfortunately that particular display isn't in the US. We get the crappy W2600H-PF, which uses a TN panel instead. Reply
  • darklight0tr - Wednesday, June 17, 2009 - link

    isn't available in the US is what I meant to say. Reply
  • Sabresiberian - Saturday, June 27, 2009 - link

    Well that's just goofy that Americans can't buy it, lol!

    I don't want a larger dot pitch anyway for a monitor, which is why I use 1920x1200 @ 24" (.27 dot pitch). The 26" 2600 models are 1920x 1200 too, and have a .287 dot pitch; too big imo. Got more 'screen door' effect already than I like.

    ;)
    Reply
  • adder - Wednesday, June 17, 2009 - link

    well AU optronics made P-MVA and then it was replaced by the newer and much improved A-MVA,the sony Z4xxx series of lcd uses the AMVA which are as good as the S-PVA in viewing angles and contrast.
    AU optronics never made S-MVA which is made by CMO or chi me optronics.
    Reply
  • JarredWalton - Wednesday, June 17, 2009 - link

    Oops!

    s/S-MVA/A-MVA/g

    Sorry for the error - I get stuck thinking of everything "Super" whatever and forget that MVA used P and now A. Anyway, this is an AUO LCD panel and the S-MVA references have been fixed. :-)
    Reply
  • Hrel - Wednesday, June 17, 2009 - link

    there were quite a few 16:10 panels that had 170 degree viewing angles or better, which is enough for my monitor uses, which include using it as a tv. And LCD televisions generally have 178 degree viewing angles.

    So WHY are ALL the 16:9 widescreen displays 160 degree viewing angles??? Were the 16:10 monitors not TN panels??? I thought they were. So yeah, I understand getting cost down, and I'm not willing to pay much more than 200 for a monitor; so I don't want cost going up. But why are viewing angles so terrible on these new 16:9 monitors than use TN panels when the slightly older 16:10 monitors had better viewing angles??

    That needs to change NOW!!!!!!!!!! Also EVERY monitor should be LED backlit; and I'd pay a little more for RGB LED backlit.
    Reply
  • JarredWalton - Wednesday, June 17, 2009 - link

    All the older 24" LCDs were S-PVA initially, and TN is only recently coming into favor there. I think the first TN 24" LCDs showed up maybe 18 months back. The problem is, the advertised viewing angles are bunk. Maintaining a 10:1 contrast ratio is NOT "viewable" by any stretch of the imagination, and that doesn't take into account color shifting seen on TN displays. Anyway, if it says more than 170 degrees on the vertical viewing angle, it's *probably* not a TN panel. Reply
  • Hrel - Wednesday, June 17, 2009 - link

    if those monitors that said 170+ vertical viewing angles weren't TN panels AND the price got down UNDER 200 dollars for a 22" then apparently whatever panel they were wasn't very expensive. So there's no reason to not use them. Also, I agree, how they test viewing angles needs to change. I shouldn't see ANY darkening of the image or shadowing when I'm looking down on or looking up at my monitor.

    Also, anandtech needs a way to email us when someone replies to out comments on here; and preferably have us be able to read the comment and respond if we want ALL in the email.
    Reply

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