On a computer that is running an x64-based version of Windows Server 2003 or of Windows XP, 32-bit applications may not use the Domain Name System (DNS) cache. Even though the name that an application tries to resolve is present in the DNS cache, a DNS query is sent to a DNS server.
This behavior may generate unwanted network traffic. Also, name resolutions that use a DNS server may be slower than resolutions that use the cached entry.
Note This problem does not occur in Windows Server 2008.