ASP page Crawl collection source content different system of different writing

Msxml.dll 80072ee2

The specific reason is the collection of local files caused by the detailed view: HTTP://SUPPORT.MICROSOFT.COM/KB/316451/ZH-CN

I was originally a 32-bit 2003 System (Standard version), collected with msxml2.xmlhttp.4.0, a page of 9 seconds or so. Change to Msxml2.serverxmlhttp after 7 seconds or so.
When the system is changed to 64-bit 2008 system (R2 Enterprise Version), with msxml2.xmlhttp.4.0 error, with msxml2.serverxmlhttp 70 seconds or so.
Later tested with code:
<%on Error Resume Next
Response.Write "Oxml=array ("msxml2.serverxmlhttp.6.0", "msxml2.serverxmlhttp.5.0", "msxml2.serverxmlhttp.4.0", " msxml2.serverxmlhttp.3.0 "," Msxml2.serverxmlhttp "," msxml2.xmlhttp.6.0 "," msxml2.xmlhttp.5.0 "," Msxml2.XMLHTTP.4.0 "," msxml2.xmlhttp.3.0 "," Msxml2.xmlhttp ")
For i=0 to UBound (oXML)
Set getxmlhttp = Server.CreateObject (oXML (i))
If ERR Then
Err.Clear
Response.Write "Not supported" &oxml (i) & "<br/>"
Else
Response.Write "Support" &oxml (i) & "<br/>"
End If
Next%>
found that 64-bit 2008 does not support xmlHttp4.0, changed to xmlhttp.6.0 after running for 8 seconds. But with serverxmlhttp.6.0, more than 70 seconds.

Why in 2003 ServerXMLHTTP than XMLHTTP faster, and in 2008 ServerXMLHTTP than XMLHTTP slow. (mainly slow too much, about 10 times times the difference)