AOC C4008UV8 review: A 40-inch 4K monitor that might be a bit too big

I am becoming addicted to big 4K monitors. When I work, I have more windows and applications open than my operating system can typically handle, and  for working with photos there's nothing like it (except perhaps a big 8K monitor).

7.9

AOC C4008UV8

The Good

The AOC C4008VU8 has plenty of screen real estate and it can display up to four sources simultaneously. Color renders beyond the typical sRGB color gamut and has decent color accuracy for casual needs.

The Bad

Noticeable differences in off-angle views -- including the top, bottom and sides when you're sitting in front of it -- plus it's tall and the stand doesn't let you raise or lower it. There's no adaptive refresh-rate support, but ghosting is visible and only one of the HDMI inputs is version 2.0, all a disappointment for PC action gaming.

The Bottom Line

For a multitalented monitor in tight spaces, the AOC C4008VU8 4K UHD, 40-inch display might be the right fit. But overall, it's not knockout for the money.

When I decided to review AOC's 40-inch curved display, it was because I mistakenly had in my notes that it cost $600 and wanted to see if it was a good deal for a big screen on a budget. The specs sounded terrific for the money: a huge 10-bit UHD (3,840x2,160) panel with a nice selection of connection options, built-in speakers and four USB ports. 

Much later I realized it actually goes for about $900. I was ambivalent about it at $600, and am even more so for the higher price. (AU$899 seems to be the price in Australia, as well; I don't think it's available in the UK, but for reference  the US price directly converts to about £682.)

Forty-inch, 16:9 displays tend to be for commercial uses like signage and conference rooms. There aren't a lot at this particular size and only two I can find that are curved -- and the curve generally doesn't make sense for commercial applications. But the size is also an odd fit for personal use. (And the C4008VU8 also bears strikingly similar specifications  to the only other one I found, the Philips BDM4037UW, so basically there's only one.)

Everything accessible

Overall, it's pretty well designed. The monitor is easy to set up; the stand arm comes attached, and you just screw the base in with the captive thumbscrew.  Be prepared to strip off the protective plastic from every surface, which took me about 10 minutes.

The connectors are all visible and easy to get to on the back, so at least we can cross one of my pet peeves off the list -- unless you care how the back looks with everything just hanging out, since there's no cable management. I also like the single control,  a joystick that you press to power on and off and use to navigate the onscreen display (OSD) menu options. You can't remap the direct-access right/left/up/down, however. And the menu is stretched to fit across the bottom, which is odd and annoying.

You can connect it to up to five video sources and display up to four simultaneously on the screen or a with single picture-in-picture. The flexibility is nice, especially if you want to connect sources like Blu-ray players, and there's a VGA connector for legacy hardware. It also has a novel feature, Bright Frame, which lets you define a rectangle on the screen with different brightness settings to highlight or de-emphasize that region. However, it doesn't work in conjunction with displaying from multiple inputs, so you can't use it to highlight a particular source window.

AOC markets its 3000R radius of curvature as a "deep curve," which it's not. But that's a good thing: if it were as deep as depicted in the company's marketing illustrations, it would be pretty unusable. It's actually a pretty subtle curve. When you normalize it -- adjusting for screen size and aspect ratio -- the curve is roughly comparable to that of the Samsung CF791.

A 4K monitor with room to spare

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Aside from the PIP/PBP capability, there isn't a ton to care about in the onscreen menus. There are a handful of presets -- the Eco mode settings -- but all they seem to do is change the brightness and tweak the RGB balance very slightly to varying degrees. There's an overdrive mode to speed up refresh rate for games, but I didn't notice much of a difference -- there's still a lot of ghosting. 

The monitor has three gamma settings, not-so-helpfully named Gamma1, Gamma2 and Gamma3. I'm not sure why -- they each average at 2, 1.9 and 1.7, though gray white points vary widely across their ranges, and none of them are really useful. And the manual is pretty useless if you want to know what a particular setting does (for example, the Eco mode "Sports" is "Sports Mode.")  There are clock, phase and controls for overclocking, though you probably want to do that via software, if at all. Clear Vision upscales low-resolution images. 

Unpacking the marketing

At least one of the marketing claims is true: tests confirm it can display 100 percent of the colors in the sRGB gamut -- it extends beyond well into the greens and reds -- and about 83 percent of Adobe RGB, which is more than a typical general-purpose monitor. One of the monitor's unique modes is Dynamic Color Boost (DCB), which essentially oversaturates memory colors  -- blues, greens and skin tones. I don't find it very pleasing, but YMMV.

AOC says it's a 10-bit panel, and since there's no way to test for 10-bit vs. 8-bit+FRC, we'll have to take its word for it. It displays 10-bit test gradients in Photoshop more smoothly than an 8-bit display when connected to a workstation card, but that just rules out that it's an 8-bit panel.

Contrast at the center is very high, partly because the display delivers dark blacks over most of the brightness range, and that's even with the dynamic contrast setting off. Brightness tops out at roughly 285 nits; typical brightness on the default settings is about 250. Even on the default "warm" setting, white point varies significantly over the brightness range, but it's always relatively cool -- in the sRGB preset it's about 6,900K. You can get it lower by fiddling with the blue channel through the menus.

However, the company also emphasizes that "The VA panel has wide-viewing angles, allowing users to enjoy consistent color uniformity and accuracy at all angles."  That only seems to be true if you're sitting TV distance from the monitor.  When using it as a desktop display, the only place that looks correct is what you're directly staring at. You can certainly see and use the off-axis areas, but viewing angle uniformity and accuracy are nothing to boast about. The contents of off-axis areas of the screen are visiblly washed out. But this is typical of VA panels; I only call it out because AOC does. I didn't see any flicker, though I don't usually (the C4008VU8 uses direct backlight control rather than PWN, so in theory you shouldn't see any).

Additionally, the uniformity isn't great, and there's noticeable vignetting (darkness) around the sides of the screen. There's a uniformity setting in the OSD, but it looks worse.

This is why where you sit relative to the screen matters, and it's complicated by the height of the display; too much of it is off-angle. And it's why the inability raise or lower the display becomes a problem. You can tilt it a bit forward and slightly backward, but that's all.

You'd think having all that screen real estate would make it great for work, but the low-contrast off-angle viewing, which represents most of the display, the height and the distraction of coarse text rendering -- despite an above-average pixel density of about 110ppi, you can see individual pixels at working distance, or at least I can--  just doesn't do it for me. If this were a TV, the optimal viewing distance would be a little over 3 feet/0.9m, which doesn't work in a lot of setups. For instance, I sit at most about 26 inches/66cm from my biggest displays at work, and that feels pretty far. And many desks aren't even deep enough to sit that far back.

But it might suit if, in addition to using it as a PC display, you also want to watch 4K UHD video from further back in a tight space, and given its low input lag (about 14 milliseconds via a Bodnar sensor), it might make a good console partner as well.

However, it's not as bad at PC-based fast-paced gaming as I'd initially thought it would be -- even without adaptive refresh I didn't have much problem with tearing in Doom, playing at 1440p to achieve a 120fps-plus frame rate, but that will vary by game engine. I had stutter problems with Bioshock Infinite in 4K, but that could be my system (GTX 1080) in combination with the game. In any case, the height of the monitor made riding the Skylines in BI slightly nauseating, possibly because too much motion took place in my vertical peripheral vision. And it looks good, off-angle viewing constraints notwithstanding. 

Also, the tiny, tinny, echoic speakers fire out the back. They're better than nothing, at best.

Not for everyone

Even if it weren't $900, I think the C4008VU8 fits a relatively narrow set of needs. If you need something that does double-duty as a PC or console monitor and TV in a relatively small space -- think dorm room or Manhattan studio -- and your budget can stretch that far, it might suit you. Otherwise, I recommend opting for something in the 32- or 34-inch range if you like 'em big but less expensive.