Introduction

While notebook hardware has steadily improved over the years, outside of the recent MacBook Pro with Retina Display there haven't really been any moves forward in improving desktop real estate in some time. In fact, for productivity-oriented users this continues to be a major reason for sticking with a desktop setup (if not a desktop system): more monitors, more space to work in. This fact of life has resulted in a bit of a niche market in the form of small, USB-powered screens.

We've tested both of GeChic's OnLap monitors and found that while they were flawed in their own ways, they were still able to expand useful work space without incurring too much of an inconvenience in terms of size or power requirements. Yet GeChic's screens need an HDMI or D-SUB port in addition to a USB 2.0 port for power, and if for one reason or another your notebook doesn't offer one of these, you're out of luck. Enter solutions based off of DisplayLink's USB technology, which are able to add another screen driven entirely over USB. Solutions like the screen we have on hand today, Toshiba's catchily-named 14" USB Mobile LCD Monitor. Here's the spec sheet:

Unlike the GeChic OnLap monitors we've reviewed here and here, which benefited from being driven off of the notebook's GPU, Toshiba's 14" monitor leverages DisplayLink's USB technology (which Jarred outlined here back in 2008). While DisplayLink has USB 3.0-based solutions slowly making their way to market, Toshiba's monitor still uses USB 2.0. Most of the remaining specifications are pretty weak, but this is a laptop designed primarily for office work as opposed to anything that demands color accuracy.

How Does it Work?

As a quick and dirty primer, DisplayLink basically uses on-the-fly compression as needed to stream data over USB to the DisplayLink-enabled monitor. What's important to note is that this means there's no GPU, dedicated or integrated, directly feeding the monitor, and as a result most of the heavy lifting has to be done by the CPU. That also means that gaming is mostly out of the question. Toshiba's monitor wasn't even exposed as an option for any of the games in our notebook testing suite.

I did try to run Duels of the Planeswalkers 2012 windowed and then drag the window over to the Toshiba monitor, and it did seem to be running well, but when I tried to maximize it, both screens were basically caught in a flickering loop. The only way I was able to break the system out of the loop was to shut it down completely.

Nearest I can tell, DisplayLink's technology seems to present itself as a virtual monitor driven by the GPU, and then takes that data and funnels it through the USB connection to the external screen. It's impressive that it works at all, but remember that the funnelling requires on-the-fly CPU-based compression, and you'll see what that means later on.

Setup, by the way, is incredibly easy. While Toshiba includes a driver disc with their monitor, there's a driver readily available for download on Windows Update for Windows 7 as well. Plug the monitor in and let the drivers auto-install, and you're ready to go.

Screen Quality

Since we're talking about a 14" monitor being powered entirely off of a pair of USB 2.0 ports, producing a quality image is actually a fairly low priority. Toshiba's Mobile Monitor uses a 14" TN panel, but thankfully eschews the glossy finish that GeChic opted for on their screens. Still, picture quality is pretty dire: the screen is less than ideal for video and certainly inadequate for any kind of serious, color-sensitive image editing work.

Toshiba rates the Mobile Monitor at a brightness of 220 nits and a contrast ratio of 400:1, which is almost comically exaggerated (just like GeChic's ratings were). Here's how the Mobile Monitor stacks up compared to the two GeChic screens:

At least partially due to the smaller screen size but also undoubtedly also due to not having to power a DisplayLink chip, GeChic's screens are able to produce better brightness than Toshiba's can. While Toshiba's screen also demonstrates a slightly better percentage of the AdobeRGB1998 gamut, it's not exactly a major win either, and the delta-e is absolutely horrendous--almost like our calibration software just doesn't work with the USB-based display, which is entirely possible. Honestly it's fairly easy to notice the Toshiba screen just isn't producing super accurate color, but given what it's intended for, this is something we can live with.

It's also worth mentioning that while the Toshiba Mobile Monitor has a brightness control, there are only two settings, making me wonder why they bothered with two brightness buttons. The figures I listed above are at full brightness; the low brightness setting is half the white level and black level.

Performance

Here's where things get a bit dicey and where the difference between a display driven by DisplayLink and a display driven by a proper GPU surfaces. First, let's take a look at a basic metric: power consumption. Since these screens are all being driven off of the notebook's power, we can hook our test system, Acer's Aspire TimelineU, up to our Kill-A-Watt meter while plugged in and get a basic idea of how much power they pull.

I connected each monitor (one at a time), set it to clone, and then dragged a Gamutvision screen around the desktop to give it some work to do. The increased brightness of the OnLap 1302 seems to take its toll on power consumption, but DisplayLink's CPU overhead is an even bigger hit. In fact, during testing, while the GeChic displays worked fine, the bottom half of the Toshiba Mobile Monitor actually cut out completely. The complete image came back after a reboot, but this is worth noting nonetheless.

In more casual use, the Mobile Monitor held up a lot better. It was able to play back 720p YouTube video with relative ease, and it's certainly fine for any basic desktop tasks. I also like the form factor of Toshiba's solution a lot more; while GeChic's displays both use clunky mounting mechanisms to attach to a notebook or flimsy stands made out of green rubber blocks, Toshiba's screen comes built into a nice leather folio that folds open into a stand. True, it's not physically attached to the notebook like GeChic's displays are, but I honestly prefer having a better stand.

The quirks of the Mobile Monitor stem more from the DisplayLink technology than anything within Toshiba's power. When testing video I was able to detect a slight lag between video and sound (nothing major), and the system has a hard time resuming from sleep mode with the Mobile Monitor attached. The Mobile Monitor will produce a picture while the main system display won't. None of these quirks manifest while using GeChic's solutions, but that's because GeChic's solutions are essentially basic screens that happen to use a USB cable for power instead of a standard power cable.

Conclusion: Depending on Your Needs

What we're left with in testing Toshiba's 14" USB Mobile LCD Monitor is having to evaluate our priorities. If you need an additional screen for your notebook, there are certainly other options available, but the known quantities I can discuss are Toshiba's display and GeChic's OnLap 1302 (the 1301 having essentially disappeared not long after the 1302's introduction).

In terms of form factor and picture quality, I actually find Toshiba's solution preferable. The wraparound folio that turns into a monitor stand is a nice touch that's worlds more functional than GeChic's silly rubber blocks. While overall image quality is superior on the GeChic displays, their glossy finishes pick up dirt and dust something fierce, and their viewing angles aren't quite as good as Toshiba's Mobile Monitor. Overall, the aesthetic of Toshiba's product is cleaner and more professional, and I'm personally fine not having to modify my notebook to attach another screen to it.

However, in terms of actual performance and usability, the GeChic OnLap 1302 is vastly preferable. Unless you don't have any open HDMI or VGA ports, being able to use your onboard graphics instead of DisplayLink's solution means not having to deal with any of the quirks that come with using DisplayLink. The technology is impressive and definitely fills a niche, but it's demonstrably inferior to having an actual video output from an actual GPU.

Finally, there's the price. A trip to NewEgg shows the Toshiba 14" USB Mobile LCD Monitor selling for $179 (or $170 elsewhere), while GeChic is asking $199 for the OnLap 1302. Given that GeChic's screen doesn't have to license a chip from DisplayLink and doesn't come with a nifty folio cover, it's pretty easy to argue that these prices should either be reversed or better yet, the OnLap should just be cheaper than Toshiba's screen.

Ultimately what I'd really like to see is something like the Mobile Monitor that can also use an HDMI, VGA, or DisplayPort input. The DisplayLink monitors available on the market basically force you to use the DisplayLink USB input instead of offering it as a value add (or, alternatively, offering HDMI input as a value add). If Toshiba's 14" USB Mobile LCD Monitor had an HDMI input on it, this would be a clean sweep. Unfortunately that's not the case, and so it's going to boil down to what compromises you're willing to make. Both products are fine and will get the job done, but neither one is perfect.