Editing xml files with long lines is really slow in vim. What can I do to fix this?

I edit a lot of xml files with vim. The problem is that, because of the long lines, navigation/editing in vim is extremely slow. Is there something I can do (besides turning off syntax highlighting/filetype plugins and filetype indentation) to be able to edit these files without all that lag?

It's really frustrating that a trivial thing such as syntax highlighting is being handled so poorly by vim. I don't remember this being an issue with any other editor. I really like using vim and I hope there is some way to fix this.