HP ZR2740w Versus Asus PB278Q: QHD 27" Monitors, Tested

Features
By Christian Eberle
published

Until cutting-edge UHD (3840×2160) displays hit the mainstream, most enthusiasts have to be content with QHD monitors at 2560x1440 pixels. In the lab today, we have two more 27-inch QHD screens: the ZR2740w from HP and the PB278Q from Asus.

Results: Pixel Response And Input Lag

To perform these tests, we use a high-speed camera that shoots at 1,000 frames per second. Analyzing the video frame-by-frame allows us to observe the exact time it takes to go from a zero-percent signal to a 100% white field.

The pattern generator is placed at the base of each monitor so that our camera can capture the precise moment that the front-panel LED lights up, indicating a video signal is being received by the monitor. With this camera placement, we can easily see how long it takes to fully display a pattern after pressing the button on the generator’s remote. This testing methodology allows for accurate and repeatable results when comparing panels.

Both panels finish squarely in the middle of the pack for panel response time. It’s interesting to note that just because one monitor brand uses the same panel as another doesn’t necessarily mean that they will match in response metrics. For example, the Asus PB278Q draws a white field three milliseconds faster than the Samsung S27B970D, even though both monitors employ the same Samsung-made PLS part. The HP is only slightly behind at 26 milliseconds.

Now let’s check out the overall input lag numbers.

The AOC I2757FH retains the lead in our comparison of recently-tested IPS screens. While one might think that its lower 1920x1080 resolution is a factor, the other 1080p monitor on the chart, ViewSonic’s VX2770Smh, is slower than both the Samsung and ViewSonic 1440p panels. The two subjects of this review are at the back of the pack by a few milliseconds, but still well ahead of the Auria EQ276W. The deciding factor here is in the design of the monitor’s input circuit board. Each manufacturer uses its own PCB, and we’ve seen companies that modify screens like the Auria with high-performance boards that not only improve input lag, but also allow for higher refresh rates. As always, pursue such mods at your own risk!

Christian Eberle
Christian Eberle
Contributing Editor

Christian Eberle is a Contributing Editor for Tom's Hardware US. He's a veteran reviewer of A/V equipment, specializing in monitors. Christian began his obsession with tech when he built his first PC in 1991, a 286 running DOS 3.0 at a blazing 12MHz. In 2006, he undertook training from the Imaging Science Foundation in video calibration and testing and thus started a passion for precise imaging that persists to this day. He is also a professional musician with a degree from the New England Conservatory as a classical bassoonist which he used to good effect as a performer with the West Point Army Band from 1987 to 2013. He enjoys watching movies and listening to high-end audio in his custom-built home theater and can be seen riding trails near his home on a race-ready ICE VTX recumbent trike. Christian enjoys the endless summer in Florida where he lives with his wife and Chihuahua and plays with orchestras around the state.

36 Comments Comment from the forums
  • KOKing
    I've had one of these HPs at work for a couple of months (replacing an early 24" 1920x1200 IPS), which I've set fairly low), but as this review says, it's not really necessary. I was a little disappointed that, possibly because of the aspect ratio change to 16:9, it doesn't _feel_ like a lot more screen real estate.
    Reply
  • Immoral Medic
    Add 120hz, THEN it's enthusiast level.
    Reply
  • bit_user
    Where are all the OLED monitors? They should be cheap and plentiful, by now!
    Reply
  • SIDDHARTH MISHRA
    Useless review, the uniformity on these screens is pathetic, tried three of each, the color temp difference across the screen is over 1000K. Toms has very poor reviewers, only prad.de and overclockers.ru do reliable screen reviews. And btw the U2713HM is regularly on sale for $500 or so, the ZR2740W is now an overpriced relic lacking even an OSD.
    Reply
  • cangelini
    SIDDHARTH MISHRAUseless review, the uniformity on these screens is pathetic, tried three of each, the color temp difference across the screen is over 1000K. Toms has very poor reviewers, only prad.de and overclockers.ru do reliable screen reviews. And btw the U2713HM is regularly on sale for $500 or so, the ZR2740W is now an overpriced relic lacking even an OSD.Screen uniformity is covered on page eight, and low points on both screens are discussed.
    Reply
  • flong777
    Am I right by saying that the Asus monitor has more accurate color and better grayscale performance.
    Reply
  • Marcus52
    Surprised that the Asus has slightly better lag results, as one of the reasons for not having an OSD is to reduce lag, and it can make a big difference. Of course, how you measure lag can get different results, and I've seen much lower numbers for the ZR2740w:

    http://www.tftcentral.co.uk/reviews/hp_zr2740w_v2.htm

    tftcentral is showing the HP as having far less lag than the Asus panel.
    Reply
  • ceberle
    The Asus certainly calibrates better than the HP; mainly because it can be calibrated. The HP is slightly better out of the box for grayscale and its chromaticity is also a touch better. Both screens have identical color to the eye. Only the instruments can tell the difference.

    Christian
    Reply
  • ceberle
    Regarding the lag results: It's hard to compare numbers from one review to another when the testing methods are so different. With our high-speed camera procedure, the only fair comparison is between the monitors we've tested. I would defend our response test as definitive though. Actually watching the screen draw in slow motion leaves no room for interpretation. The lag test is also consistent since we use the same signal chain for every screen. There is never a change in video cards, drivers, peripherals or any other device that might affect the result.

    Christian
    Reply
  • dgingeri
    I have the HP ZR2740w, and have for over a year now. It's a great looking monitor, and it performas well by my standards, but suffers from a significant lack of both reliability and support. HP's support is massively fragmented. It took me over three hours on the phone to get to the department that actually handled the support for this monitor. (It is a "Commercial" monitor, not business or personal. It's splitting hairs mighty thin, but that's the way HP's support is separated out.) When I finally got through, they sent a tech with a replacement monitor the next day. However, it also has two major hardware issues that render it useless when they occur. Most of the first run monitors had the power supplies die within months. The second run monitors had a serious issue with the control boards. All of them have issues with the USB hub, but it least the monitor keeps working if you don't have the USB cable plugged in. As an owner of one, I would not, under any circumstances, recommend this monitor to anyone.

    HP: the perfect example of a company falling apart because it is both too big and too fragmented.
    Reply