Loading a XML file via WWW is slow, How can I make it faster?

Below is my code.

WWW w = new WWW(someAdress + "Content.xml"); yield return w;

and it takes more time than I imagine. it takes almost 1 second, while much bigger image file takes alot less time to download.

i can't understand what makes downloaing a xml file is slower than downloading a image file.

i suspect www is doing somekind of reading whole texts beside just downloading it.

if someone knows anything make it faster, please reply it. or if it it is impossible, please tell me what is reason of slow speed.

also, i wonder that

xDoc.LoadXml(w.text);

code make it faster, like loading images using formmated file or turn off unnecessary options.