I first heard about these on TWiT about six months ago where the TWiT panel agreed that they would die off in development and would probably never become an actual product. Well they were wrong. There now is such a thing as a USB connected computer monitor. Seriously. This monitor connects to your PC via a USB port!
For a computer monitor to work via a USB port it has to be driven by the central processing unit (CPU). This means all of the graphics work has to be handled by the computer’s main CPU.
Graphics work is intense.
Driving the video to your computer screen takes awesome amounts of processing power even when you are just working in Word or Excel, but when you start to do image or video editing the amount of processing power becomes insane, and then if you move on to real-time massively multi-player online games video processing shifts up to a whole new level.
The very reason that video cards—which incorporate their own dedicated built-for-graphics GPU (graphics processing unit)—came into existence was to take this massive processing load away from the main CPU and free it up to do the real work; and not have to worry about getting stuff ready to put on the screen. For the average screen about 1,500,000 pixels are updated about once every 30th of second. This takes a huge amount of work—even when the screen is not doing anything it is still being updated.
The article about the USB connected screen does point out that it would not be suitable as the main or primary screen, due to the processing power it would drain from the main CPU, but that it might have a use as a secondary screen.
This line of thinking also make no sense at all. About 95 percent of all video cards in all desktop computers now have a DVI connector on them. This can be used to connect two screens to the video card (once you buy the right DVI to dual-analogue converter cable).
Okay. I can hear some of the think-ahead thinkers saying: “But what about for notebook users?”
Notebooks would be the last type of computer you want to plug a USB screen into. Firstly the horsepower of the CPUs in notebooks are effectively, generalising massively, on average, 60 to 75 percent as powerful as the CPUs in desktops; so you wouldn’t want a USB screen robbing 30 or 40 percent of that power to render the screen. Secondly, by default, all notebooks have two screens when you connect an external screen. They have the external screen, which can be either the primary or secondary, and they have the screen they have attached to them, which can be the primary or secondary. And with Windows XP, Vista, and Windows 7 either screen can be an extended screen which then gives you a really wide screen desktop (two screen side-by-side effectively making up a single desktop).
So I am at a loss to see why anyone is going to buy a USB connect screen that is going to take gobs of horsepower off your main CPU in order to drive it. Just don’t make any sense to me at all. Even if they gave them away; which will not be the case.
Oh … You can click the graphic to go the article about the USB screen that I came across. To make things worse it is listed as No. 4 on the a Top 10 list of “Cutting Edge Computer Accessories” for 2011. Sob.