We've seen plenty of big- and wide-screen monitors in recent months, but the AOC 40-inch 4K monitor (C4008VU8) is something else. This TV-size display has 3840 x 2160 resolution, spread across nearly 700 square inches of glossy LCD panel. The giant 4K display offers more than just size and high resolution; it also boasts 10-bit color and a curved surface for more immersive viewing. If you're looking for a monster, this will fit the bill.
The AOC C4008VU8 features a 40-inch curved LCD panel. It's an almost overwhelming amount of screen, measuring 21 inches tall and nearly 36 inches across. With a 16:9 aspect ratio, the display is big enough to fill most of your peripheral vision, or to be comfortably viewed at a distance. The entire monitor is 35.7 x 24.8 x 9.7 inches (including the stand) and weighs a hefty 26.12 pounds.
The 40-inch display has a gentle curve, with a radius of 3000R.
That's shallower than the Samsung CHG70's overly aggressive 1800R (smaller numbers mean a tighter curve) but slightly deeper than the LG 34UC89G (3800R).
AOC does what it can to avoid looking like a TV, with a white plastic chassis and a silver-finished, V-shaped stand. The stand comes attached, with the base requiring some basic tool-free assembly with a thumbscrew. The attached stand arm can be removed, but you'll need a Phillips-head screwdriver.
The stand allows you to adjust the angle of tilt, but the height is not adjustable. You can, however, use a VESA mount to hang it on the wall or attach it to a sturdy arm mount, as the monitor will accommodate 100-millimeter fittings.
The C4008VU8 is outfitted with a good selection of ports, with two HDMI connections (one HDMI 1.4, one HDMI 2.0), a pair of DisplayPorts, a VGA connection for older devices and a quartet of USB 3.0 ports (one with extra power for charging smartphones and other devices) with an upstream USB 3.0 type-B connection.
For audio, there is a line-in jack as well as a line-out for connecting speakers or headphones. If you want to pipe your PC audio through the monitor's built-in speakers, you'll need an audio- patch cable.
We do wish that the dual HDMI ports were both using the 2.0 standard, since the older HDMI 1.4 connection has lower bandwidth. The biggest issue for this display is that having a smaller pipe for video data throttles 4K content to 24 frames per second (fps).
That's fine for most movies and TV shows (which are traditionally shot at 24 fps to begin with) but other 4K content, like video games, will need to use the other HDMI port for higher frame rates.
The multiple video inputs also let you use the one display like a multimonitor setup, with picture-in-picture and picture-by-picture modes that allow you to break up the 40-inch screen into quadrants that offer 1080p resolution.
You can effectively set up four separate devices, or you can run multiple video connections from a single PC (provided it can handle outputting to four 1080p monitors).
Watching the trailer to Avengers: Infinity War in 4K, I could make out small details, like the hairs on Peter Parker's arm, or the buckles on Captain America's suit. Colors were reasonably bright, and details were crisp. However, I noticed that the sheer size of the display meant that issues with viewing angles creep in along all four edges of the panel. A full- screen purple image, for example, was pink tinged along the edges of the display -- the inevitable side effect of such a large, curved screen.
The sheer size of the 40-inch display was excellent for other uses, however. Visual real estate is a more apt description here than usual, as the TV-size monitor fills almost your entire field of vision, and the high resolution makes it excellent for such things as viewing blueprints at full size, or tiling windows filled with detailed information, like spreadsheets and stock tickers.
If your professional use demands maximizing the viewable space in front of you, it's hard to beat this monster.
Gaming, on the other hand, was a bust. I tried to use the display while playing Grand Theft Auto V, but the display had real issues with ghosting, and showed a slight smearing effect when objects moved quickly. Some of this was alleviated by setting the Overdrive mode to "Strong," which helped a bit by reducing the response time, but the ghosting remained. There is also no variable refresh rate, so anything other than 60Hz introduces screen tearing.
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On a lark, I tried gaming over both HDMI connections. When I connected the PC via HDMI 2.0, I could play at full 4K resolution with admirably smooth frame rates. When connected to the same system over the older HDMI 1.4 standard, however, action became choppy as I was limited to frame rates in 24-30 fps range. (Ghosting remained an issue on both connections.)
Lab test results
Given the monitor's 10-bit color support, we had high expectations, and the range of color offered by the display was indeed quite impressive, with a 144.9 percent sRGB color gamut. By comparison, the LG 34UC89G (126 percent) and the Dell P3418HW (129 percent) are slightly less expansive, while the HDR-capable Samsung CHG70 outperformed them all (154 percent).
Color accuracy also tested well, with a Delta-E rating of 0.24 (closer to 0 is better). That's very good, but both the Dell P3418HW (0.08) and the Samsung CHG70 (0.09) registered better numbers.
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Finally, the brightness averaged a decent 286.8 nits. For a monitor limited to standard dynamic range, that's pretty good. The LG 34UC89G topped out at 292 nits, while the Dell P3418HW averaged 263 nits. HDR-capable displays, like the Samsung CHG70, can go as high as 600 nits, but only for HDR-formatted content.
Built into the giant display chassis are two 5-watt speakers. They aren't very good. The volume output is extremely weak - I had to crank up the PC sound to about 75 percent just to make out dialogue in a movie trailer - and the sound that came out was tinny and echoey. Watching the trailer for Avengers: Infinity War, the sweeping cinematic score was horribly weak. Big orchestral hits had no impact, and dialogue sounded lousy. Thanos' deep, gravelly voice sounded like someone speaking through a tin can, and Tony Stark sounded like his voice was echoing down a hallway.
Navigating the various display modes and settings of the C4008VU8 is done using a clickable joystick on the back of the monitor. Its position on the back right side of the chassis is easy to reach, and once you're accustomed to the directional controls, it's simple to make your way through the monitor's menus.
Unfortunately, the on-screen display isn't particularly polished. The menu runs along the bottom of the screen, stretching across three-fourths of the enormous display. The basic options are easy to navigate, and give you the ability to adjust the luminance and color, and activate features like picture-in-picture mode.
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There are also a few unexpected options. There's the Bright Screen mode, which lets you highlight one quadrant of the panel when running it as a four-screen multi-monitor display, literally highlighting one of the four feeds. Unfortunately, it applies only to input coming from the PC, and can't be used to highlight one screen from among multiple sources.
The menu options for Eco mode aren't particularly helpful, either. There are various modes listed: Standard, Text, Internet, Game, Movie and Sports, but these appear to be strictly presets for brightness and contrast. If you wanted to select, say, Game mode, you will need to find the separate Overdrive menu option (also found in the Luminance menu) and set it to Strong to shorten the response time. When activated, the response time drops from 15 milliseconds to 5 ms.
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Other options include multiple gama presets, a Clear Vision mode for upscaling content, a low blue-light mode that filters out harmful rays and Dynamic Color Boost mode, which lets you ramp up the saturation for blue skies, green grass and skin tones.
Unfortunately, the documentation that comes with the monitor (a quick start guide and a user's manual) do little to explain these opaque menu options. The documentation also leaves you to your own devices to understand the arcana of A/V jargon and abbreviations, so be ready to Google if you don't know what DDC/CI refers to (protocols for letting your computer communicate with the monitor for power and settings), or if you're unsure if D-Sub refers to a VGA connector (it does).
AOC also has a software version of the display settings, called i-Menu, which gives you all of the same menu options and equally scant explanation of the various settings.
The AOC C4008VU8 is probably bigger than most people are looking for. If, however, you want a desk-dominating 40-inch display, be it for viewing architectural plans or executing stock trades on its multiple screens, the AOC C4008VU8 fits the bill with its expansive 4K display, curved design and better-than-average performance. The audio leaves a lot to be desired, and there are some real rough spots in the on-screen display for settings, but on the whole it's a good-looking monitor. It just happens to be enormous.
If you want something a little more reasonable, the wide-screened Dell P3418HW is good for office workers who can make do with 1080p resolution. And Acer Predator X34 gives you a great gaming monitor with 4K and a curved screen that won't bowl you over.
Credit: Laptop Mag