Pit the reference GTX 580 in SLI and 3D surround vs the reference Radeon 6970 in crossfire and Eyefinity.
Most people out there seem to be building their mulit-monitor configs with 3 1080p monitors, so the article should deal with 5760x1080p resolutions.
Measure the 2D performance of 580s with 1.5GB and 3GB to determine whether the additional VRAM makes any sort of difference (can I turn AA or other effects up with more VRAM?).
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