When you connect to a website your computer sends info back and forth. Some of this information deals with resolving the site URL to its IP address. This is DNS information and its used so that you will not need to ask for the site IP each and every time you visit the site. Although WinXP and win2000 has a fairly efficient DNS cache, you can increase its performance by increasing the size. You can do this using the registry hack below:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters]
"CacheHashTableBucketSize"=dword:00000001
"CacheHashTableSize"=dword:00000180
"MaxCacheEntryTtlLimit"=dword:0000fa00
"MaxSOACacheEntryTtlLimit"=dword:0000012d
Simply make a new text file and rename it to dnshack.reg. Then copy and paste the above code into it and save it. Then click on it to merge it into the registry.
Another advantage of this hack is that it reduces your reliance on updating your DNS records, so with the DNS attacks recently, its probably a good idea.