Overlord Tempest X270OC, 27" 120 Hz IPS Gaming Monitor Review

Results: Grayscale Tracking and Gamma Response

The majority of monitors, especially newer models, display excellent grayscale tracking (even at stock settings). It’s important that the color of white be consistently neutral at all light levels from darkest to brightest. Grayscale performance impacts color accuracy with regard to the secondary colors: cyan, magenta, and yellow. Since computer monitors typically have no color or tint adjustment, accurate grayscale is key.

Since we had to measure the Tempest using PC-generated patterns, we made sure to turn off any LUTs before starting.

If you simply plug in the X270OC, this is the grayscale performance you get. Green errors are visible at all brightness levels above 10 percent, and they're most obvious in document windows due to the white backgrounds. The issue isn't as bothersome in games or while watching video. Compared to a calibrated image, it does look a little flat, though.

CalPC facilitates an extremely precise calibration. Most OSDs give you, at most, 100 steps in their RGB controls. Using a LUT means all 256 levels of each color can be adjusted to achieve an essentially perfect result.

And now, back to the comparison group:

An average error of 5.9 Delta E is high for any monitor. In the X270OC’s case, the values range from 2.6 to 7.6.

That the Tempest doesn’t finish first with its LUT calibration is a testament to BenQ’s XL2720Z, more than anything. A result of .49 Delta E reflects a really low grayscale error.

Gamma Response

Gamma is the measurement of luminance levels at every step in the brightness range from 0 to 100 percent. It's important because poor gamma can either crush detail at various points or wash it out, making the entire picture appear flat and dull. Correct gamma produces a more three-dimensional image, with a greater sense of depth and realism. Meanwhile, incorrect gamma can negatively affect image quality, even in monitors with high contrast ratios.

In the charts below, the yellow line represents 2.2, which is the most widely used standard for television, film, and computer graphics production. The closer the white measurement trace comes to 2.2, the better.

We’re only showing one gamma chart because it corresponds to the un-calibrated and calibrated state of Overlord's X270OC. CalPC didn’t need to make any changes. The miniscule hump at 90 percent represents only a 1.4 cd/m2 aberration; it's completely invisible.

Here is our comparison group again:

The Tempest has the flattest gamma tracking in the group, right out of its box. That's particularly important in games, where you want to be sure you’re seeing every tiny detail.

We calculate gamma deviation by simply expressing the difference from 2.2 as a percentage.

Only that tiny error at 90 percent prevents the Tempest from posting a perfect gamma result. Again, you won’t be able to see anything wrong. Detail rendering on this monitor is as good as it gets.

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107 comments
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    Top Comments
  • rishiswaz
    I wonder why they don't just have another model with cherry-picked panels that they ship at 120 out of the box
    12
  • Other Comments
  • oudmaster
    the price is interesting with these specs !
    any idea if there will be a similar monitor spec but 4k resolution ?

    thanks,
    2
  • oudmaster
    the price is interesting with these specs !
    any idea if there will be a similar monitor spec but 4k resolution ?

    thanks,
    -6
  • wtfxxxgp
    Crickey me...this is a monitor of note it seems! At that price point, I find it incredible. Well done to Overlord! The only issue I have now is... will the price increase as a result of all the buzz this will generate? This is probably going to be my next monitor, depending on exchange rates...
    5
  • Shneiky
    4K at 120 MHz? Not in the next 5 years.
    -8
  • Swiperd3
    Driving QHD to 120 FPS at the max graphics detail is sure as hell will require A LOT of horsepower. Will TOP-SLI/CF-x2 be enough for modern FPS games?
    3
  • Traciatim
    Wow, you get this with one of the variable sync techs and you have yourself one fantastic monitor.
    2
  • envy14tpe
    Thank you Thank you Thank you. I've been dying to see a review on this monitor.
    6
  • Reaver192
    Yeah, I've been waiting fir this for too long. I wanted one of these months ago but they have been out of stock. Such a sweet deal
    2
  • avatar_raq
    This is the holy grail of PC monitors, if only it comes with 120 Hz guaranteed out of the box.
    7
  • yogalD
    I wish it had a strobe backlight though, that would make it perfect
    3
  • Durandul
    If it had an option for Display port, that would have been almost perfect. That being said, I use DVI anyway, so who am I to complain.
    5
  • MonsterCookie
    This is already a step at the good direction. Even the price in $ looks decent.
    Question is how much will this cost here in Europe.

    Also, now make the same thing happen in a 30" format with 2560x1600 resolution, and than I am definitely opening my wallet.
    2
  • mapesdhs
    MonsterCookie, alas I doubt that will happen. A few years ago, 1440 and 1600
    height monitors were priced basically the same, ie. expensive. Back then, top-end
    GPU reviews tended to use 2560x1600 as a typical max res test for gaming. But
    then buying patterns evolved, the usual feedback between pricing and demand,
    people tended to opt more and more for 1440 displays instead. As a result, when
    I wanted to get a 1600 IPS a while ago, I was amazed to find 1600 hieght displays
    were about 4X more expensive than 1440 IPS models.

    Presumably it suits the industry to home in on a more typical standard, and for
    the moment, beyond HD, 2560x1440 seems to be it. Very unlikely the industry has
    any interest in pushing 1600 height to the masses, so probably the next main step
    up will be to 4K, or as I wish they'd call it instead, quad-HD.

    Ian.
    2
  • ubercake
    The specs look goood, but the key is they don't guarantee 120Hz for all OC monitors:
    http://overlordcomputer.com/blogs/news/7384176-the-overclock-overview

    It's like hoping you'll get an i7 that will have a stable OC to 4.5Ghz 24/7. It's the luck of the draw.
    I don't much like putting my money on hope. If they did have a guarantee or just sold a monitor that shipped to my house with 120Hz capability, I'd be more likely to hand over my cash.

    You know darn well they make sure the review site is getting a good one.
    2
  • daglesj
    So does it work fine at say 90Hz and if so is that an improvement?
    1
  • npyrhone
    Thanks a million for the review! This will be next monitor. Hallelujah! Lacking a decent non-TN gaming panel, I've played with a pro 24" CRT for all these years.
    1
  • npyrhone
    A few answers and corrections concerning ideas thrown around in this thread:

    1) Yes, This works perfectly at 90Hz. Yes, it is a great improvement. Much greater improvement is 60->90 than 90->120.

    2) All monitors are from this day to the future to come 16:9. So, its useless to fancy 16:10 monitors anymore, they wont be coming ever again.

    3) 4K 120Hz gaming monitors wont be coming, either. At least not in the foreseeable future.

    4) Overclocking this is not luck of the draw. They all come at least 96Hz, and the great majority work 120Hz.

    5) The lack of displayport etc is what helps keeping input lag low.
    3
  • rishiswaz
    I wonder why they don't just have another model with cherry-picked panels that they ship at 120 out of the box
    12