X

Connect your monitors via USB and save the planet?

DisplayLink looks at the amount of power savings achieved by connecting displays via USB vs. DVI.

Eric Franklin Former Editorial Director
Eric Franklin led the CNET Tech team as Editorial Director. A 20-plus-year industry veteran, Eric began his tech journey testing computers in the CNET Labs. When not at work he can usually be found at the gym, chauffeuring his kids around town, or absorbing every motivational book he can get his hands on.
Expertise Graphics and display technology. Credentials
  • Once wrote 50 articles in one month.
Eric Franklin
3 min read
DisplayLink's message: get more done and save on energy, all through the magic of USB. DisplayLink

According to DisplayLink, a Microsoft Research study says that using two or more displays can increase productivity by as much as 50 percent. The company also notes that University of Utah researchers have shown that users of multiple displays make up to 33 percent fewer mistakes than those working on a single monitor.

Now, in its own study released Wednesday, DisplayLink says that using multiple monitors simultaneously via USB consumes less power than using them via DVI. To plug multiple monitors into one system traditionally requires that you use a discrete graphics card solution with dual DVI ports. Right away that's theoretically more power, since discrete solutions take more energy to run than integrated solutions. With DisplayLink, you'd simply be using the USB port to connect, so there would be no need for a dual DVI card and the integrated graphics would suffice.

At Interop, an IT conference and Exposition in New York this week, DisplayLink is leaning on its study results to push the energy efficiency of using DisplayLink to connect multiple monitors via USB.

In its study, DisplayLink measured the power needed for a desktop PC to run one to four LCD monitors. Two identically configured systems were used--one equipped with DisplayLink-enabled USB-to-DVI adapters and software, and another with dual-DVI discrete graphics cards (the most common type of dedicated multidisplay board). Power consumption was measured at the entry of the computer power supply to gauge total system power usage under different system loads.

The researchers found that adding a display with a USB adapter incurred an average increase of only 4 watts per display, or a 7 percent increase in power consumption.

The discrete graphics solution, meanwhile, used considerably more power due to the necessary installation of dedicated hardware inside the computer. When driving a single display, the discrete card used, on average, an additional 34 Watts of power, or a 67 percent increase in power consumption--without the benefit of any additional displays. When the system was configured to drive four displays (which required the installation of a second card), the power consumption jumped to an average of 117 Watts, or an increase of 132 percent compared to the single-display configuration.

Other findings include:

  • The USB graphics solution used up to 80 percent less power to drive an extra display than a discrete graphics solution.
  • The discrete graphics solution consumed as much, if not more power, than an extra LCD monitor. This causes the overall system-power consumption to more than double if three or more displays are used, or an increase of 128 percent.
  • When three additional displays were connected to the system using USB adapters (for a total of four displays), the system used only 22 percent more power (a total of 62 Watts) than needed to drive a single display.
  • USB multidisplay technology works with notebooks and small form-factor PCs, where a discrete graphics solution is not possible, allowing multiple-display users to use more power-efficient notebook PCs in place of traditional desktop PCs.

You can read a white paper on the study by going here and see a video demonstration here. If you're not interested in more info, well, you probably stopped reading when your eyes started to glaze over during the second paragraph.