I have an Airport Extreme card with the Atheros AR5416 chipset in my Mac mini (late 2007 rev.) and it worked perfectly in Leopard. I could connect to my roommate's Airport Extreme just fine on its 802.11n network. But with multiple tries installing Snow Leopard it just has not worked to connect to that same network. Despite the antenna only being connected to the connector for 5GHz networks, I can connect only to 802.11g (2.4GHz) networks but not 802.11n (5GHz) networks. If the network card was defective I would expect Leopard to have similar issues but it was rock solid. Right now I am using an Airport Express as a bridge through ethernet to get internet connectivity. This is something I fully expect to deal with in Linux or even Windows with old drivers, but certainly not on Apple's own OS on their own hardware. Has anyone else had similar issues with Snow Leopard? Whether you do or not, what chipset does your Airport Extreme card use? You can get this info from Apple menu -> About this Mac -> More Info -> Airport -> Firmware version. From what I understand, Apple is still using both Broadcom and Atheros chipsets in their Airport cards, so I'm curious to see if it's an issue with Atheros chipset drivers in particular. Thanks for any assistance.