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How DisplayPort multi-streaming delivers new levels of multi-monitor madness

Michael Brown | April 22, 2013
DisplayPort 1.2's multi-streaming feature lets you rock four monitors—from a laptop, no less!

When a vendor sends us a demo system, it typically take great care to ensure that we experience the system exactly as the maker intends us to. So when VESA, the trade group responsible for the DisplayPort standard, said that it was sending PCWorld a multiple-monitor demo system similar to the one it exhibited at CES in January, I expected it to arrive bundled with a detailed guide and all the software needed to present DisplayPort in its best light.

Imagine my surprise when an MSI GX60 gaming laptop, two 24-inch Dell U2413 displays, and a 21.5-inch HP Elite L2201x showed up in the PCWorld Labs without so much as a user manual for any of the four devices. "Wow," I thought. "They must be pretty confident that setting all this up will be self-evident."

As things turned out, setup was  pretty much self-evident. The GX60 has HDMI and VGA video outputs, but obviously I was more interested in its Mini DisplayPort. Both of the Dell monitors have full complements of digital video inputs (HDMI, DVI, and full-size DisplayPort, along with ports labeled 'DisplayPort In' and 'DisplayPort Out'), but the HP display has only a DisplayPort input.

I connected the full-size DisplayPort on the first Dell to the notebook, plugged a second cable to that monitor's DisplayPort Out, and connected that to the other Dell's DisplayPort In. Then I attached a third cable to the second Dell's DisplayPort Out and plugged it into the HP display to complete the chain.

The notebook was now driving four displays, including its own. This setup was possible because all of the gear--except the HP at the end of the chain--supported DisplayPort's multistreaming feature. So if you're thinking of scrounging up three old DisplayPort monitors and duplicating my experience, you're out of luck. On the other hand, you can press one old monitor into service (if it supports DisplayPort, and if you install it at the end of the chain). DisplayPort is a common feature on professional and business monitors, but it shows up much less frequently on consumer displays.

I hope that changes, because DisplayPort rocks.

The monitors you use don't have to be the same size, and they need not support the same resolution. As I found out later, that's why VESA sent us two models (the Dells) that had a native resolution of 1920 by 1200 pixels and one (the HP) that had a native resolution of 1920 by 1080 pixels. The laptop display at the beginning of the chain also has 1920 by 1080 native resolution, but the monitor at the other end doesn't have to be positioned last in the array.


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