I'm running the C2758 (without the bug) on a 1GB connection, VPN, snort, pfBlockerNG, and a few other plugins @ 44C and 2% CPU with no active heat sink. The CPU will spike at a max of 11% when downloading 850MB/s over VPN and the temp only varies by a degree or so.It will be for a dual WAN setup with max uplink speed of 100mbps (atleast for now). I intend to run openvpn and snort on it. I was considering Supermicro C2558/C2758 boards but they dont have active cooling and not sure whether hardware bug is still present on the boards being sold on Amazon. The mini-itx i have is fairly ventilated and i have fans mounted on hard-disk trays like so.
I actually want active cooling in the router and dont care so much about noise. I thing Supermicro A2SDi-4C-HLN4F would do the job for me.If money is no object, check something like this out. I'm using two for 2 ends of my Site to Site VPN (both C2758s) and they are AWESOME. They are silent (0bviously, being fanless) and keep my CPU at 30C and 22C (cold basement). I have gigabit internet between both nodes and push 400-500Mbps across the VPN daily.