content: USB, even 3.0, has high burst speed but it cannot usually sustain anywhere near Max burst speed. If hdd is less than 7200rpm than that can also make boot go slower but not to the kind of timing you're seeing. As for wifi, if it's only working some of the time then something is going on during boot preventing the driver from loading at times. WiFi tends to be the most annoying thing to deal with as everything is designed for Windows and/or Mac with Linux as an afterthought. Same thing can happen with newer motherboards. It can take awhile for drivers to hit your distro but it's rarely a showstopper.