I’ve been working with multiple displays since at least 2004. Back in those days I had a 17″ PowerBook G4 with a PCM/CIA card that provided a second external DVI output. It was slow, but it worked, and for the programming I was doing the lacking performance was not an issue.
For the last few months, I’ve been using a Sorbent USB 2.0 adapter to provide a second video output for my Mid-2011 MacBook Air, so I had two external displays, and the laptop itself for 3 total. The problem is that this MacBook Air doesn’t have USB 3.0, and USB 2.0 just doesn’t have enough throughput to drive a large display, so it had a lot of lag—too much to really be acceptable.
I’d been looking around for solutions. The problem is that all of the Thunderbolt docks can only really drive a single external display unless one of your monitors is itself a Thunderbolt display, which can work via Thunderbolt pass-through. But recently there have been more and more USB 3.0-based docks that support Mac OS X.
So I picked up a Kanex KTU10 Thunderbolt to eSATA Plus USB 3.0 adapter, and an Etekcity USB 3.0 dual monitor dock for my late-2011 MacBook Air. This dock has two USB 3.0 ports, 4 USB 2.0 ports, and two display outputs (HDMI and DVI), and the Kanex adapter should in theory provide a USB 3.0 port which the dock needs.
After a little dance with installing the latest DisplayLink driver (2.3 beta), they totally work.
So for about $200 (only a tad more than the cost of one of the single-display Thunderbolt docks), I’m running with three screens again, and the performance is perfectly acceptable for most things I will ever need to do.
Plus I’ve got gigabit Ethernet, more USB 3.0 ports, and an eSATA port which will be great for backing up my machine to an external drive.
Overall I’m very pleased.