Question: My Windows 2003 server standard DHCP server takes 30-45 seconds to give out an IP to XP clients. I've never seen one this slow before. The server is not overwhelmed.

We are on 100 Mbps switches. 

Any ideas or suggestions?

Answer: 
Launch NetworkMonitor or Wireshark and observe the traffic between the client and server. It's likely a network related problem. You could also use Windows Server's Perfmon to watch DHCP statistics in the various stages of the [DORA process](http://www.google.com/search?q=dhcp+dora). Also, [check to see if there's another DHCP server on the network](https://serverfault.com/questions/8526/how-do-i-find-if-there-is-a-rogue-dhcp-server-on-my-network), although the symptoms don't sound like what I would expect.

If you want to try blindly twiddling options, you could try restarting the DHCP service to see if that clears things up. You could also rebuild the DHCP database. I'd recommend observing the network traffic and DHCP statistics first.

Is the indexing service or an antivirus client scanning the DHCP directory? If so, that's bad.
Packet never lie

You can capture all the data under XP client and analyse them.
From which you may find answer.

You can find how much times Broadcast\Discover\Request packets the XP client sending and how long time DHCP server response them.

In a word,in packets world you can find more info than application operation and your sense.