I'd say way more than enough power. You want that much power, electricity, heat, noise?
PFSense is not a UTM appliance, doesn't need a lot of power. I've played with a lot of hardware and various *nix distros, I've come back to PFSense….because of QoS features. I run it on one of my old IBM Thinkpad laptops, a mid-range P3. Only 256 megs of RAM. Onboad Intel NIC, I stuck in a Linksys PCMCIA NIC...she runs great. 5x users in the house..2 of which are VERY heavy users. Plus I have an IPSec VPN tunnel to my office, do a lot of other VPNs to other clients. 8 meg connection. Under the heaviest of loads on the network...I never got CPU utilization above 35%.
Laptop..nice and small, quiet.