Hi, how do I determine which card are suitable for a multi-monitor setup?
If it has a DVI and a HDMI output, does that mean I can plug two monitors in, or does that just mean that I can either plug in a DVI *or* HDMI monitor?
And how is the linux support for multi-monitor? I've only ever tried it on a laptop, never a desktop.
Nearly all AMD vid cards support >1 monitor easily. amdcccle ("control panel" for AMD drivers) will easily allow you to configure more than one monitor, and KDE can configure similar setup with its own display settings.
My setup includes a pair of 2569x1600 IPS displays using an AMD 7870 (pick the most ram possible; I have 2x2Gb in crossfire config). Check your monitor specs, but the first DVI port is usually a DVI-D port (2 ports in one) which is required to drive very high res displays like mine. The newest R280 and above I believe had dual DVI-D ports available.
Also, the newer high end cards have two dual dvi ports, but that's not required. I currently use one DVI-D port, and a display port (with display port to dual DVI-D adapter) to match the ports on my IPS monitors.
You'll find most include some various combo of dual and single DVI, display port, and HDMI ports. All can be used at the same time.
With a single card, you should be able to easily connect and configure 2 1080p (or better) type displays. Main hassle is when you get to bandwidth needed for high res monitors (4k, or like mine, 2x 2560x1600) is just finding the right combo of cables :-) 100% stable in my setup, zero complaints.
In a single "multi-head" desktop on linux, windows can be dragged between monitors, all the usually nice "eye candy" works fine on both, and you'll never look back at a single monitor. You can configure some setups with 2 "single" X displays, but I found that rather annoying myself :-P
If any questions, drop me a PM and I'll do my best to help.