Hello - I am trying to use the Gigabit ethernet port on my iMac (2.16 GHz Core 2 Duo - 10.5.6). I have gone into system preferences and change the settings to manual, 1000baseT, full-duplex, flow-control, custom MTU of 7936. When I apply the settings, I lose all network connectivity. When I look in the Network utility it shows a Link Speed of 1 Gig, but a Link Status of inactive.

I can take that exact same CAT5 cable out of the back of the iMac and plug it into my Macbook Pro and use the Gig settings right away. I can also use the Gig settings on a mini used in my media room. This seems to point to the NIC card in the iMac, but I wanted to check with others before I lug this thing into the genius bar. Is there anything unique on the iMac that I need to tweak to get Gigabit working?

Thanks - Paul