I'd like to set up one of my ThinkPads as a router, and am wondering how much of a difference it would make if I used a 1GB USB Ethernet adapter as opposed to a 1GB PCMCIA Ethernet adapter for the WAN connection. Is it possible to measure any difference in performance, and if so how would I measure it? Thankfully both devices are supported by FreeBSD, but my preference would be the PCMCIA card as it fits snugly and is unlikely to get knocked which the USB adapter might since it sticks out quite a bit.