The most performant way to validate XML against XSD

I get a string variable with XML in it and have a XSD file. I have to validate the XML in the string against the XSD file and know there is more than one way (XmlDocument, XmlReader, ... ?).

After the validation I just have to store the XML, so I don't need it in an XDocument or XmlDocument.

What's the way to go if I want the fastest performance?