I've got a Time Warner cable ISP package (RoadRunner), and the modem they gave me doesn't allow me to specify which DNS servers to use; it always uses whatever the upstream dhcp server gives it. I prefer to use OpenDNS on my home network, so i've configured a couple of my PCs manually in the Windows adapter settings for IPv4 such that their IP addresses are obtained via DHCP, but the DNS server settings are fixed to the OpenDNS server IPs.

Now, when I startup Windows on these PCs, it always takes 2-3 minutes to start receiving responses from the DNS servers; any request before that times out. While not debilitating, this is quite annoying. Any ideas why this might be happening?