does that mean XHTML better/faster for internet browsing on a traditional computer?
In theory, the rules are simpler and violating lots of them results in an error message rather than spending processor power to recover. In practise, mobile devices now have fast enough processors that this doesn’t matter.
The theory also applies to desktops, but suffers from a few problems. The main one is that Internet Explorer doesn’t support XHTML (note that a document which conforms to the xhtml specification but is served as text/html is treated as HTML, so doesn’t count), and Firefox doesn’t do incremental rendering (so it doesn’t show anything to the user until the entire document is downloaded, making it take longer before the user can start reading).