I didn't really think of thin clients.
I guess I am just thinking ahead, and really wanting to have headroom with power and resources.
I host my own datacenter in the basement, so I have ProLiant servers (16GB RAM each) running at all times. The extra 50 Watts isn't that much of a deal. I heard of a larger PC only using 50 Watts at load.
I just want to test pfSense, and remove my router I have now. The router is ISP lent, and it's extremely slow and often reboots.
But, I am keeping in mind that I do not want a fan running in the background which would usually be loud on these desktop PCs.
I'll definitely check that out, and feel so much better that someone said my idea might be overkill. Now I am confident that I can handle the bandwidth.