DNS DoS?

I experienced a major slowdown in hsd recursive resolution the other day while visiting a website that attempted to pull resources from around 200 handshake domain names, many of which have no webservers and many of which are misconfigured etc. I think the volume of DNS queries actually bricked my local hsd recursive resolver and all websites loaded extremely slowly if at all on my computer. We should make sure that the unbound resolver we use can access multiple threads or otherwise deal with a high volume of requests, even if they are all from a single user.