NVIDIA's card looks more like a GeForce GTX 285 card than a GTX 480. NVIDIA has implemented several changes to the cooler which certainly help the card keep cooler than GTX 480. Also there is an extra space around the fan opening to allow for easier access to air when running in SLI.
NVIDIA's GeForce GTX 580 requires two slots in your system.
The card has two DVI ports and one one mini-HDMI port. According to NVIDIA the card also supports DisplayPort if board partners want to use it. Unlike AMD's latest GPUs, the output logic design is not as flexible. On AMD cards vendors are free to combine six TMDS links into any output configuration they want (dual-link DVI consuming two links), on NVIDIA, you are fixed to two DVI outputs and one HDMI/DP in addition to that. NVIDIA confirmed that you can use only two displays at the same time, so for a three monitor setup you would need two cards.
NVIDIA has included an HDMI sound device inside their GPU which does away with the requirement of connecting an external audio source to the card for HDMI audio. The HDMI interface is HDMI 1.3a compatible which includes Dolby TrueHD, DTS-HD, AC-3, DTS and up to 7.1 channel audio with 192 kHz / 24-bit. NVIDIA also claims full support for the 3D portion of the HDMI 1.4 specification which will become important later this year when we will see first Blu-Ray titles shipping with support for 3D output.
You may combine up to four GeForce GTX 580 cards in SLI for increased performance or improved image quality settings.
Here are the front and the back of the card, high-res versions are also available (front, back). If you choose to use these images for voltmods etc, please include a link back to this site or let us post your article.