Other than those already mentioned there aren't many more rear I/O options. There are, of course, the usual PS/2 keyboard and mouse ports, and an optical S/PDIF output alongside six 3.5mm audio jacks, but that's all you get. With air-flow and cooling in mind a large, yawning gap between the I/O connectors exists to accommodate a beefy heat sink. This not only draws heat from the power regulators beneath it but also disperses heat via a winding S-shaped heat-pipe rising from the MCP. Abit calls this the Silent OTES (Outside Thermal Exhaust System) and, while it's usually sufficient for heavy loading, your case needs to have adequate airflow if it's to work efficiently.
Tucked away close to the capacitors above the CPU socket are the main four-pin CPU fan header and a three-pin system fan header. Both are tricky to get at, more so if the board is already installed and cabled up. Two additional fan headers make it possible to set up a fairly comprehensive board-driven cooling system. Additional power requirements are met through a standard four-pin 12V auxiliary connecter near the right-hand edge of the board, while a four-pin Molex power connector, sited alongside slot one, provides extra juice for the PCI Express slots.
In total there are six expansion slots with two standard PCI slots and two x1 PCIe slots accompanying the two graphics slots. With no redundant spacing between them you'll block a PCI and a PCIe slot by installing a pair of double-width graphics cards.
In audio terms, the KN9 SLI utilises the ever-popular Realtek ALC883 7.1+2 HD codec offering 7.1-channel output plus an additional two independent stereo channels for multiple streaming. The codec also supports Beam Forming technology though no hardware is included to exploit it. S/PDIF digital in and out also feature in the ALC883's specifications but despite the presence of solder points and screen printing on the board for both input and output, Abit only includes an output. As we've come to expect, audio quality was excellent but it can't compete with discrete high-end offerings.