AOC E2251FWU 22-inch USB display

USB DisplayLink monitors are a relatively new breed of peripheral for Macs and PCs. The technology creates a virtual display on your Mac/PC, compresses it, and then sends it over USB 2.0 to a monitor that uncompresses it. You would think this could cause a lag, but the transfer is almost un-noticeable by the naked eye. It is basically an extra monitor that connects to your USB port and frees your monitor port for other uses.

A few years ago, the photo frame-sized displays started appearing as small external USB DisplayLink monitors. Then came 16-inch 720p monitors last year that thin clients could use as terminals for about $100.

This month, however, a company called AOC released an impressive 22-inch 1080p DisplayLink monitor for both Mac and PC. To put it in perspective, those are the same pixels and inches as the current, smaller iMac. It really is a lot of extra monitor for playing. The AOC retails for $200, but it is currently selling for around $160.

What is exciting about this monitor is that it is powered entirely by the USB port. There is no AC adapter on this monitor or VGA/DVI/DisplayPort/etc.—just one, thin USB 2.0 cable running from the computer to the back of the monitor. USB solely powers the 22-inch 1080p display. I have been using the AOC on a 2010 MacBook Air and was surprised that it was fully functional, even when the MacBook Air was not plugged into the AC adapter.

I set up my 2010 Air with a monster 30-inch 2,560-by-1,600 DisplayPort monitor and plugged in the AOC DisplayLink 1080p display for an absurd amount of pixels coming out of the Air. How did it fare?

The first thing I love about this display is that it is super light and super thin. It weighs 5.8 pounds with the stand—less than many laptops. The monitor is bus-powered, so it does not need an AC Inverter or much of a motherboard. That helps keep the weight down, but it is also razor thin (almost erring on the side of flimsy) at just barely over a centimeter thick.

I was able to fit the whole monitor (with stand removed) into my Ful Powerbag backpack without issue. As an experiment, I took it to the river and did some work outside with it plugged into my Air. The 2010 Air with two years of heavy use gets about two or three hours of hardcore use normally (screen full bright, Wi-Fi, browsing, videos, etc.). With the 22-inch AOC USB monitor attached, I got about 50 minutes of use from 100 percent to blackout. That is not bad for those thinking of using this as a presentation device.

A lot of that battery drain is the USB power out, but some of it is the DisplayLink Manager application running in the background. On the Air, it idled at about 1 percent, but it shot up to near 20 percent to 30 percent of the CPU when watching a Hulu movie on the display. Watching a full 1080p movie shot it up even further to the mid-40 percent of one core use. That is about what Flash typically uses, but it is not something my Air cannot handle.

You will need to install the DisplayLink Manager for Mac or PC. The current stable version is 1.7, but a recent 1.8Alpha update fixes some bugs and enables monitor rotation. I was fine with 1.7.


Even with extra-unused CPU cycles, I still noted a slight lag in frame rates for full-screen videos. This was something I could not shake. Even when watching H.264 movies with nothing else open, I still saw some dropped frames. The video is watchable, but you definitely know something is not right.

Therefore, I would not recommend this monitor for people who want to watch 1080p videos—at least not from a MacBook Air. Perhaps one would have better luck with a Mac Pro doing the data chomping. It is nice for people who need more space on their Mac desktop. In this manner, the AOC delivers in a big way. Without having a hardcore machine, I can have two external displays connected to my MacBook Air. I use my main display as usual, and then I put all of my chats/tweets/alerts/emails off to the side on the AOC.


The color and brightness are both fine, especially for a $160 monitor that is powered by a USB port. Actually, considering that, the monitor is damn impressive. Who would have thought you could drive a 22-inch 1080p monitor from the USB port on a MacBook air?! Colors are generally accurate, and it is bright enough for work, even outside in sunlight.

My biggest beef, and hopefully something that DisplayLink can fix in upcoming versions of its Mac software, is that DisplayLink shuts down when the MacBook is closed. Due to the way the Air works, it does not recognize the display while closed unless another monitor is hooked up. I tried tricking it by unplugging the DisplayPort, but it just put the Air to sleep. As far as I know, you must use this monitor while the laptop is open. This obviously will not be an issue for desktop users.

The Future:

In addition to the software suggestions noted above, USB 3 DisplayLink products are in the pipeline that promise much larger displays with hopefully less lag. DisplayLink promises more viewing options including additional wireless options. As Macs go to USB3, more options will evolve.

Bottom Line:

I can recommend the AOC E2251FWU for anyone who wants to quickly, easily, and cheaply add a 22-inch 1080p display to his or her current system. The same goes for Mini users who want to add a portable display, as well as MacBook users who want a portable big screen for the road. It is light, thin and performs well for presentations and as a second monitor—so long as you do not hope to watch full-screen video without frame loss.

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