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Acer Predator XB271HK 27-inch UHD G-Sync Monitor Review

Gamers seeking Ultra HD resolution have few choices but an excellent new G-Sync monitor has just appeared from Acer, the XB271HK sporting a 27-inch AHVA screen. We’re checking it out in our lab today.

Viewing Angles, Uniformity, Response And Lag, G-Sync

To learn how we measure screen uniformity, please click here.

Acer lists the XB271HK as an IPS-type panel but it’s plain from our photos that it’s of the AHVA variety. This technology prioritizes viewing angles by reducing the thickness of the grid polarizer. The result is only a slight output reduction when seen from 45 degrees to the sides or above. The color shift is a touch green but nowhere near as much as a typical IPS panel. Detail retention in the vertical plane is also exceptional when compared to any other LCD display variant.

Screen Uniformity: Luminance

Our sample measures well in the black field test. All the zones are within a hair of each other except the bottom right. You’ll recall that zone also skewed the ANSI test a bit. If not for that, this result would likely have been a top-finisher. Even so, we still have no visual problems to report. IPS glow or light bleed are not in evidence here.

Here’s the white field measurement.

In the white field test we can see a slight center hotspot, and the bottom third of the screen measures a little higher than the upper six zones. It’s just barely visible in the test pattern but doesn’t seem to affect any of the content we viewed during gameplay or productivity testing.

Screen Uniformity: Color

Color uniformity is among the best we’ve seen from the 80-plus panels we’ve tested since 2013. The only panel in this group that actually has a visual issue is the XG2700-4K. The rest are within our preferred tolerance levels. This metric varies from sample to sample, but we rarely see a display with serious issues in this test.

Pixel Response And Input Lag

Please click here to read up on our pixel response and input lag testing procedures.

Only the XB280HK seems to be able to break the 20ms barrier for 60Hz screens. The AOC, also a TN panel, is next fastest. While you might see a 6ms difference in motion blur, it’s unlikely anyone would see a one or two millisecond variation. Combined with G-Sync, we have no complaints about the motion processing of the XB271HK.

Here are the lag results.

Acer leads the pack in input lag with both its Ultra HD displays. The TN panel seems to have the edge, which isn’t surprising given its 8-bit color depth. That the XB271HK can manage a 61ms result with a native 10-bit rendering is impressive. When it comes to gaming at such high resolutions, input lag is only one of many concerns. An underpowered video card will introduce judder and other artifacts that also serve to harm the gaming experience.

Gaming With G-Sync

As long as one stays within the adaptive refresh range of a particular monitor, there is no visual difference between G-Sync and FreeSync in a gameplay situation. However when dealing with Ultra HD resolution and its 60Hz rate cap, the bottom of the range becomes important because the operational window is smaller. We’ve reviewed a couple of FreeSync screens that came with an uncomfortably high lower limit and made setting game detail levels difficult. With a G-sync screen though, you’ll never get tearing below the minimum refresh rate because frame doubling takes over. For example, if the bottom is 30Hz and the frame rate drops to 29, the screen starts refreshing at 58Hz and drawing each frame twice. So all you see is a gradual increase in judder until the game becomes unplayable due to excessive input lag.

Another thing we’re trying to decide is just how much Ultra HD resolution improves the gaming experience. With a QHD display, framerates can be pushed beyond 60Hz which makes the whole thing much smoother. When you consider that the biggest disadvantage of any LCD panel is its inherent motion blur, it makes sense that faster refresh is the way to smooth motion. Playing at a maximum of 60Hz is fine but not exceptional when it comes to fast on-screen movement. And after testing many gaming monitors, it looks to us like 75Hz is a pretty good threshold to shoot for. At that speed, motion blur is virtually non-existent, even without the use of overdrive or backlight strobing.

In the XB271HK’s case, we performed our usual torture tests playing Tomb Raider, Far Cry 4 and Battlefield 4. Perceptions were pretty much the same as we’d seen on previous Ultra HD panels with adaptive refresh. Tear-free rendering – check. Reduce motion blur with overdrive – check. Judder when framerates drop below 40 – check. Acer’s overdrive implementation is fairly conservative which means there’s no ghosting but not a significant blur reduction either. We settled on Normal as the best setting. And G-Sync’s frame doubling ensured that the experience didn’t change when things got slow.

  • chumly
    Bummer about the response times. The other Predators, the x34, z35, and the smaller 16:9 XB270 variants were all on point (less than 15ms absolute input lag).

    The world is still not ready for 4k (but getting closer). 2 more years, 2 more years.
    Reply
  • chumly
    actually now that I'm comparing tom's review to another review on the same monitor, the response time numbers are not adding up. lag of 16 - 32ms, is one to two frames of lag at 60Hz, according to TFT central, they call this class 2; class 1 (less than 16ms) being optimal for gaming. They have this same exact monitor with only 4ms between signal process and pixel post (much much faster). What's up? Your response time numbers seem to be a lot higher than they should be.
    Reply
  • jasonelmore
    Newegg recently had this model for $679. Pretty good deal for a 4k gysnc
    Reply
  • picture_perfect
    We think motion quality is more important than resolution. When you move up to 75Hz and beyond, things like motion blur fade into the background. Those kinds of artifacts no longer distract from gameplay. With adaptive refresh, tearing is a thing of the past at any resolution, but we’d still rather have those high framerates. So do those extra pixels make up for this? We’d have to say no at this point.

    YES. This is an opinion gamers need to know before buying a 4K monitor and one that has been missing from your previous reviews. KUDOS for finally dishing out some common sense. These resolutions are too high.
    Reply
  • eklipz330
    18177986 said:
    Bummer about the response times. The other Predators, the x34, z35, and the smaller 16:9 XB270 variants were all on point (less than 15ms absolute input lag).

    The world is still not ready for 4k (but getting closer). 2 more years, 2 more years.
    that prediction falls in line with mine... but for me, that means it's an excellent time to buy a "stop gap" monitor now.

    3440x1440, 120hz, OLED HDR 34" monitors with low latency to be a thing in 2-3 years. but until we have the hardware to drive that resolution, it makes no sense to wait. i think a 35" 2560x1080 144hz VA panel is amazing right now (for gaming).
    Reply
  • Sam Hain
    For me (and this is just my opinion and gaming needs), I cannot justify 4K 60Hz, regardless of price-point, monitor size, response times, manufacturer, etc. at the moment...

    Perhaps 4K w/GSync, hitting 100Hz and we have a winner... But of course, then comes that killer price tag.
    Reply
  • ubercake
    I had this monitor for a day and returned it because of the backlight bleed. It was equivalent of the poor viewing angles you see on a TN monitor because the bottom right corner was very bleached out unless you physically moved your head to center on the bottom right corner.

    I then picked up a PG279Q which has less backlight bleed.

    I found both monitors to have great performance, but found the backlight bleed on both to be distracting.

    I really don't think either Asus or Acer is where they need to be when they charge $800 for a 1440p IPS monitor. These panels may perform well, but they are not great IPS panels from a backlight bleed standpoint. They should be priced around $500 because of the low-end IPS panels. You know what I mean if you've used a good IPS panel.

    Hopefully, they'll stop ripping people off one day.
    Reply
  • Sam Hain
    18179002 said:
    I had this monitor for a day and returned it because of the backlight bleed. It was equivalent of the poor viewing angles you see on a TN monitor because the bottom right corner was very bleached out unless you physically moved your head to center on the bottom right corner.

    I then picked up a PG279Q which has less backlight bleed.

    I found both monitors to have great performance, but found the backlight bleed on both to be distracting.

    I really don't think either Asus or Acer is where they need to be when they charge $800 for a 1440p IPS monitor. These panels may perform well, but they are not great IPS panels from a backlight bleed standpoint. They should be priced around $500 because of the low-end IPS panels. You know what I mean if you've used a good IPS panel.

    Hopefully, they'll stop ripping people off one day.
    In your XP, would Asus build-quality stand as being "better" or does another manufacturer in this realm of gaming-spec monitors stand out in your opinion? I'm not in the market yet... BUT am getting close. Thanks!

    Reply
  • AlistairAB
    At bestbuy.ca this monitor is $1288 after tax in Canada and the LG 27UD68 is $616. Swap freesync for gsync and save over 600 dollars and you get the same quality panel (or is the LG a higher quality one?) I wish I could spread the gospel of the LG monitor faster, as hardly any sites are mentioning the first inexpensive freesync 4k monitor has arrived, making the price points of all the older ones obsolete.
    Reply
  • Bezzell
    Gsync prices are out of control, as are their GPUs.
    Reply