Having done with the main parameters, let’s now check out the special feature of the 940UX, its USB connection. So, we need a computer with a USB port (any standard USB 2.0 port will do – there are no special requirements to it), Windows XP (the drivers for Vista were under development at the time of our tests; the support for alternative OSes was not even on the agenda), and a powerful enough processor.
The last requirement comes from the fact that the computer’s graphics card cannot output the contents of its frame buffer or anything else into the USB port. It means the monitor driver has to emulate the graphics card on the software level. Thus, it is a purely 2D solution. 3D is not supported since the processor’s capacity wouldn’t be enough to emulate it.
We took a PC with an AMD Athlon 64 3000+ to test the monitor. Not the fastest CPU available today, but quite typical for an office machine, and the SyncMaster 940UX is meant for office use in the first place.
We were somewhat disturbed at finding no driver on the included disc as well as on the Samsung website. It turned out to be simple, though: the driver was stored inside the monitor. The monitor’s USB hub has four ports. Two are wired outside, one serves the DisplayLink chip, and one more is connected to flash memory the driver is stored in. So, as soon as you connect the monitor to a PC, a new removable disk appears in the system. It is identified as a CD-ROM rather than a flash drive, probably to be compatible with Windows’ standard auto-start feature. The driver installer is auto-started from it.
The installation was performed without problems, adding a few new items into the list of devices:
Why two UbiSync monitors? Samsung was kind to offer us two samples of the 940UX so that we could test multi-monitor configurations and the screenshot shows the moment when both monitors are connected (and the second monitor is plugged into the first monitor’s USB hub rather than directly into the computer’s USB port). The third monitor, denoted as “Plug and Play”, is the default monitor of the computer, connected to the graphics card.
Here’s the monitor settings screen in Windows. It shows the default monitor connected to the ordinary graphics card and two Samsung UbiSync monitors connected to the virtual DisplayLink graphics cards.
On the monitor itself the USB input works like the two traditional video inputs. When you switch to the USB input, a standard notification appears for a few seconds.
Everything came to life at the first attempt, in the triple-monitor configuration right away, although this computer, having a GeForce 2 MX card with an analog output only, couldn’t have hoped for such an abundance of display options earlier. Each monitor worked in its native resolution: 1024x768 on the default 15-incher, and 1280x1024 on each 940UX.
What about the CPU load? It was zero when the USB monitors were displaying a static picture. The virtual graphics card’s driver seems to process and transfer data only when the picture on the monitor must be changed.
Nothing changed when we displayed the Windows Task Manager screen with the CPU load graph. The data stream proved to be not intensive enough to load the CPU well. It’s only when we opened up a web-browser on one UbiSync and were scrolling a web-page with text and pictures in it that we managed to get an additional (i.e. additional relative to the same activities as performed on an ordinary, hardware graphics card) CPU load of 30%. A quick scrolling of a web-page is not a very frequent task while the 3000+ CPU is a low-end solution today – so this is quite a good result, we guess.
We also tried to play a movie in a full-screen view. It was not a problem except for additional load on the CPU – it increased to 50% almost. The second monitor, connected to the first monitor’s USB hub, was feeling all right, still displaying a Windows Desktop in its native resolution of 1280x1024, but we didn’t try to launch a second movie on it…