With Eyefinity, one card can drive up to six displays (depending on the model, of course). AMD states that all 5000-series GPUs support Eyefinity. However, it falls to the graphics card manufacturer to decide whether and how Eyefinity will be implemented on a given card. As of this writing, only the 5800 models have Eyefinity enabled in CrossFire mode, and it seems reasonable to expect that bandwidth plays a part in this decision. With the Radeon HD 5890 freshly placing AMD back in the lead for desktop GPU performance, the last thing AMD wants to risk is a bunch of 5400-series buyers trying to span Left 4 Dead 2 across three screens at maximum settings and wondering what why it isn’t playable. Having the display connectivity for multiple displays is one thing, but putting the muscle behind those pipelines is something else, and vendors need to pair their output paths and GPUs appropriately.

Fudzilla-All HD 5830 to be non-reference
Fudzilla-HIS to bundle Modern Warfare 2 with HD 5830
Fudzilla-XFX announces its HD 5830
Fudzilla-MSI slaps Twin Frozr II on its HD 5830
AMD Radeon HD 5830 product page