How good are USB video cards?

Are cheap external USB video cards good enough to power an extra monitor or five, and what are their pitfalls? Won't handle 3D acceleration? Take up valuable CPU cycles? Leave dirty dishes around your desk and have a bad odour?
Written by Renai LeMay, Contributor

After I published my pseudo-scientific investigation several weeks ago into the widespread problem of phantom monitor pain, quite a few readers wrote in with one simple question. "Renai," they earnestly asked me, "why don't you simply get yourself a second monitor at work?"

The answer, it turns out, is not as simple as that. But then, it never is for people like me who tinker with their hardware too much.

My ZDNet.com.au workstation is a Dell Optiplex 755, which in general terms I'm happy with, as it has a nippy Core 2 Duo CPU and 2GB of RAM. Those of you who have worked in publishing houses will know this is a bounty of processing power not normally found on journalists' desks.

However, the one problem with my slimline Dell is that its graphics card doesn't come with two monitor outputs ... in fact it doesn't even come with a DVI output. Instead, it has but a solitary VGA plug to make do with.

Consequently, the only ways I can get a second monitor working is to buy a half-height video card and do some delicate surgery on my Optiplex, or to simply buy one of these new-fangled external USB video cards people have told me about.


An external USB video card (Credit: Winstar)

You can pick one up from Aus PC-Market for slightly over $110, or more if you want a really fancy one. A cursory look at the specifications shows that most of the units can provide resolutions of up to 1600x1200 or even more, and work on a variety of operating systems.

I'm still slightly suspicious of such a solution though, as I'm not sure of the extent to which the USB 2.0 specification is geared to support extra displays (especially when it comes to 3D acceleration), and whether there would be an impact on my CPU from the extra gear.

What has your experience been with external USB cards? Good, bad or ugly?

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