gigabit switch with 100/10 router

I am wanting to have a gigabit switch connect my devices on the lan, however since it is a cheep switch it is not managed or inc's a dhcp server, so the dhcp server will still sit on the 100/10 Adsl router. The question is, will this limit the network to 100mb, does all traffic need to go via the router to be directed to the correct device, or will only a "who is" message go via the router.