Can anyone tell me if and why there was significant change in the XML parser
(or something related to it) on Windows Server 2003 for SP1.  The issue is
that we have some older software that used MSXML 2.5 interface.  After
installing SP1 the code came to a crawl.  It is a multi-threaded app and
each thread read from the same dom.  The DOM was populated before the
threads kicked off.  After modifying the code to use a later interface it
came back to life.  When running the code on the pre-SP1 system it worked
just fine.  The delay shows up when many threads are reading form the DOM at
the "same" time and there is switch from one thread to another.  pre-sp1 the
app took about 30 seconds, post SP1 it took about 6 minutes and after making
the chnage below it is back in the 30 second range.

I can accept the change now that we can say that MSXML4 is required but
would like to understand what changed and why or what I was doing wrong.

Roughly - The old code instantiated the DOM this way:
One version -
CoCreateInstance(MSXML::CLSID_DOMFreeThreadedDocument, NULL,
CLSCTX_INPROC_SERVER,
                             MSXML::IID_IXMLDOMDocument,
(void**)&m_pIXMLDOMDocument);
Another Version-
CoCreateInstance(MSXML2::CLSID_FreeThreadedDOMDocument, NULL,
CLSCTX_INPROC_SERVER,
                             MSXML2::IID_IXMLDOMDocument,
(void**)&m_pIXMLDOMDocument);
The above two crawl.

The new code does it like below and it and it comes back to the same speed.
it used to be pre-sp1

CoCreateInstance(MSXML2::CLSID_FreeThreadedDOMDocument40, NULL,
CLSCTX_INPROC_SERVER,
                             MSXML2::IID_IXMLDOMDocument,
(void**)&m_pIXMLDOMDocument);

The difference in the last 2 is:
CLSID_FreeThreadedDOMDocument vs CLSID_FreeThreadedDOMDocument40

It is almost as though the statement being made is - we want you to get off
earlier versions of the parser.  If not - go slow.
Thanks