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Results: Pixel Response, Input Lag and Blur Reduction

Asus ROG Swift PG278Q 27-inch G-Sync Monitor Review
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To perform these tests, we use a high-speed camera that shoots at 1000 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.

Since our pattern generator tops out at 60 Hz, we connected the PG278Q to a PC for the speed tests. We use the same high-speed camera (1000 frames-per-second) to film a mouse movement that tells us the total input lag and screen draw time. We film five iterations and average the results. G-Sync and ULMB are turned off, and the refresh rate is locked at 144 Hz.

The top four monitors all run at 144 Hz, while the Overlord hits 120. The correlation between screen draw and refresh rate seems pretty consistent. The 120 Hz IPS screen is just a little slower. A five- or six-millisecond result is about as fast as it gets for now. The only remaining question is: can a 144 Hz IPS screen match its TN competitors? We’ll have to wait and see.

Here are the lag results:

As expected, input lag is extremely low. Remember, this is straight-up 144 Hz with no v-sync or G-Sync. Of course, you don't suffer any lag penalty with G-Sync, but you do with v-sync turned on. Ultimately, signal rate-matching and low input lag are the best combination, which is precisely what G-Sync offers.

Motion Blur Reduction With ULMB

To use ULMB (Ultra Low Motion Blur), you need an Nvidia graphics board with its refresh rate set at 85, 100, or 120 Hz and G-Sync turned off. You can’t use both features at once.

With any kind of backlight strobing, there is a tradeoff in brightness. Luckily, the PG278Q has plenty to spare, so if you want to use ULMB, we suggest turning the backlight up to its maximum settings. That's exactly what we did for our tests.

Brightness with ULMB on is also affected by refresh rate. The lower the rate, the higher the output. Asus thoughtfully includes an OSD adjustment for the pulse width. It’s like the utility we used in the BenQ XL2720Z review. Changing the pulse alters brightness from a maximum of 100 down to a minimum of 10. The charts below show both extremes at all three ULMB-supported refresh rates.

The smallest reduction in output hits at 85 Hz, where you give up 57-percent brightness. Even this least-aggressive setting improves motion resolution significantly. We observed several moving detail tests from BlurBusters and saw obvious benefits.

Black levels change at the same rate as white levels, so you won’t really see much change in contrast. The choice comes down to your preferred light level.

Of course, the greatest measured contrast comes at a uselessly-low output level. Our favorite setting is 85 Hz with Pulse Width on 100. A ratio of 874 to 1 is still very respectable.

Choosing between G-Sync and ULMB comes down to the kind of game you’re playing. For fast motion with wide-varying frame rates, G-Sync will eliminate frame tears and stuttering. In a more fluid title where the frame rate doesn’t change as much, ULMB creates a better look. In either case, input lag and response time stay low thanks to the Swift’s speedy 1 ms panel.

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  • 6 Hide
    ubercake , August 11, 2014 9:08 AM
    That Amazon link is to the PB278Q, not the PG278Q! ARRGGGGHHHHH!!!
  • 2 Hide
    TechyInAZ , August 11, 2014 9:12 AM
    Nice! This is great since I am one of those picky guys that believes that 30fps doesn't bring a good enough gaming experience.

    But one thing I do hope for is a 144hz g-sync IPS monitor, ever since I've gotten my new Asus MX239H the ips makes a huge difference in games.

    But besides that, it is a glorious monitor, resolution is great, 144hz, and of course g sync makes it a wonderful monitor.

    But really $800? I know that it is one of the few g sync equipped monitors, but you can buy a 4k monitor for $650!
  • 7 Hide
    CraigN , August 11, 2014 9:29 AM
    Yes - please fix that Amazon link. I almost shat myself thinking that was available already.
  • 0 Hide
    apertotes , August 11, 2014 9:36 AM
    Anybody knows if the incompatibility between G-Sync and ULMB is something that will get fixed or is here to stay?
  • 0 Hide
    CraigN , August 11, 2014 10:09 AM
    Quote:
    Anybody knows if the incompatibility between G-Sync and ULMB is something that will get fixed or is here to stay?


    Pretty unlikely. ULMB requires a static refresh rate, because it has to strobe the monitor at a constant rate. GSYNC would mean that it would have to strobe in time with each frame, at a variable rate. You would introduce a lag time on the strobing if you tried to do this, since it would be at a variable rate instead of a constant one.
  • 3 Hide
    rh_dog , August 11, 2014 10:43 AM
    I know it's expensive for 2560x1440, I know it's not IPS, but to get the refresh rate @144hz and the 1ms g2g and g-sync? The few reviews for this monitor that are out there are all glowing. Come on, Asus, release the thing already, I've been waiting since the Jan announcement for this monitor. Shut up and take my money!!!
  • 1 Hide
    pchampn , August 11, 2014 11:21 AM
    Guys ROG Swift PG278Q is not even listed on Amazon. Update your links, please!!
  • 3 Hide
    Rendezvous , August 11, 2014 11:29 AM
    Omg! I need this now..... I alrdy have 800 set aside for it...I need a exact release date now!
  • 0 Hide
    agentbb007 , August 11, 2014 11:48 AM
    Asus has said on Twitter it should be in the US by the end of August. I can't wait for this, I'm checking newegg everyday to see when it shows up! I hope they have enough of these coming in because there seems to be a lot of people waiting to buy this monitor.
  • -2 Hide
    Merry_Blind , August 11, 2014 11:53 AM
    Yayy finally a review for this monitor! Thanks Tom's!

    Off to read it now! lol
  • 2 Hide
    Rendezvous , August 11, 2014 12:24 PM
    Quote:
    Yayy finally a review for this monitor! Thanks Tom's!

    Off to read it now! lol


    There have been plenty reviews for this monitor just Google it. And they have all been great reviews...makes me want it even more
  • 0 Hide
    Merry_Blind , August 11, 2014 12:24 PM
    As amazing as this monitor looks, it still sucks that you can't use ULMB with G-Sync.

    Personally, I'm sick of the crappy motion resolution in LCDs. It's not so bad in some games, but it's nigh-unbearable in certain games. My next monitor/TV WILL have Strobing-Backlights since it's the best way to get rid of motion blur.

    However, maybe someone can help me out on this, I don't understand why monitors that feature such motion-enhancing technologies seem very nitpicky with which frame rate, refresh rate, etc. it's being used with. I'm saying this because more and more TVs are coming out with such Strobing-backlight technology, and I'm pretty sure those don't require an absolute steady framerate for it to work.

    For example, if I were to connect a console to this ASUS Swift monitor, could I use ULMB in 120hz mode with a 30fps game?
  • 0 Hide
    CraigN , August 11, 2014 12:47 PM
    No, because the console won't output 120 Hz, especially not through HDMI to DisplayPort conversion.

    It's not the framerate they're being picky about, it's the refresh rate. The light has to strobe in time with when the next frame is being introduced. When the refresh rate is constant (i.e., locked at 80, 100, or 120 Hz) then the strobe knows exactly when the next frame will be displayed. You're asking the display to strobe the backlight at will whenever the GPU can put out a frame. You're essentially asking the GPU to not only handshake with GSYNC when to render a frame, but to trigger the backlight to strobe then too. The tricky part here is that's another layer where you will have to reduce response time (response from the GPU's frame being rendered to backlight being strobed) since the refresh rate is no longer constant (it's now dependent on your game's refresh rate - which is barely ever anywhere near "constant").

    How awful would your strobing backlight look if it came a few ms after your frame rendered? That'd probably screw all of the blur reduction qualities you want from it. At best, you could make an algorithm that would strobe at the *average* framerate you're outputting since framerate can rise and dip so quickly, but that could still cause a lot of problems
  • 0 Hide
    agentbb007 , August 11, 2014 12:53 PM
    Quote:

    For example, if I were to connect a console to this ASUS Swift monitor, could I use ULMB in 120hz mode with a 30fps game?

    I'm definitely not an expert on ULMB or Gsync but the blurbusters website says "LightBoost motion blur elimination is not noticeable at 60 frames per second." So even if you could get a console hooked up to the Asus Swift I don't think you would be able to notice any difference unless you get 85+ fps.
  • 0 Hide
    Merry_Blind , August 11, 2014 12:57 PM
    Quote:
    Quote:
    Yayy finally a review for this monitor! Thanks Tom's!

    Off to read it now! lol


    There have been plenty reviews for this monitor just Google it. And they have all been great reviews...makes me want it even more

    Oh I know that, it's just that I was waiting for Tom's Hardware specifically to do a review since I like their reviews!
  • 0 Hide
    Merry_Blind , August 11, 2014 1:08 PM
    Quote:
    No, because the console won't output 120 Hz, especially not through HDMI to DisplayPort conversion.

    It's not the framerate they're being picky about, it's the refresh rate.


    Ok, let's forget consoles then for a second, because I didn't think of the fact that they can't output at 120hz. If, for example, I had my PC hooked to the Swift monitor, set to 120Hz, and that the game I play has a fluctuating framerate going anywhere from 30fps to 90fps. Would I be able to use ULMB since the monitor is running at 120Hz? Despite the framerate being all over the place, and not ever at 120fps?

    Thanks for your reply btw.
  • 0 Hide
    Merry_Blind , August 11, 2014 1:09 PM
    Quote:
    Quote:

    For example, if I were to connect a console to this ASUS Swift monitor, could I use ULMB in 120hz mode with a 30fps game?

    I'm definitely not an expert on ULMB or Gsync but the blurbusters website says "LightBoost motion blur elimination is not noticeable at 60 frames per second." So even if you could get a console hooked up to the Asus Swift I don't think you would be able to notice any difference unless you get 85+ fps.

    But like I said, more and more TVs are being released with a 'Black-Frame insertion' option, and from reviews, it gets rid of motion blur very well, even for a movie, which plays at 24fps.
  • 0 Hide
    CraigN , August 11, 2014 1:18 PM
    Quote:

    Ok, let's forget consoles then for a second, because I didn't think of the fact that they can't output at 120hz. If, for example, I had my PC hooked to the Swift monitor, set to 120Hz, and that the game I play has a fluctuating framerate going anywhere from 30fps to 90fps. Would I be able to use ULMB since the monitor is running at 120Hz? Despite the framerate being all over the place, and not ever at 120fps?

    Thanks for your reply btw.


    No problem. I enjoy discussing the topic.

    Yes. You would. Because with ULMB on, the REFRESH RATE stays constant, despite your varying frame rate. The monitor (In regular, or in ULMB mode, with Gsync off) will only refresh the frame at a rate of every 8.33 ms (1 / 120Hz), regardless of your framerate. This has nothing to do with the 1ms response time. That's where your keyboard or mouse input lag comes in. This is also what causes horziontal tearing, which is what GSYNC aims to remove. If your FRAME rate is much higher, or much lower, than your monitor's REFRESH rate, you will observe lots of tearing. ULMB does not reduce tearing, just motion blur.

    You don't have to hit 120 fps to refresh at 120 Hz, but you get the most benefit out of your monitor that way. So yes, you can play ULMB at any framerate, but you *will* notice stutter if you're playing in the 90s and then drop into the 30s. This is what traditionally VSYNC tries to remove, but introduces input lag as a side effect.

    Gsync removes the stutter and the tearing with virtually no input lag. It makes it so your monitor will refresh at the same rate as your framerate. So if you set your monitor to 144 Hz, and turn GSYNC on, then suddenly your *Max* framerate becomes 144 Hz (can't update faster than the panel), and the refresh rate of the monitor (when the monitor displays new frames from the GPU) varies with the framerate of the game from any range of 35 FPS up to 144 FPS. If you drop below 30 FPS, the GSYNC module switches to traditional VSYNC.

    GSYNC can be toggled on and off from the Nvidia Control Panel. This is how you can switch between GSYNC or ULMB depending on what type of game you want to play.
  • -7 Hide
    redgarl , August 11, 2014 1:45 PM
    It's made by Asus and it is not a motherboard... stay away from it...
  • 5 Hide
    CraigN , August 11, 2014 1:49 PM
    Not sure why you feel that way. Several of their other products I own have been outstanding. My VG248QE is great and so is my G750JX laptop. Their $650 4K monitor got fantastic reviews.

    Some of their lower-end products have some quality issues I hear, but you see that in Dell, HP, Acer... It's not exactly a new trend.
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