VM AJAX CART module it's almost the same with the default Virtuemart Cart module plus 3 features:
- Cart is not preloaded
- Cart is loaded with AJAX on page load, this prevents from caching issues, you can cache entire site without worrying about the cached cart
- Can load default VM layout, this means at most cases this module will be compatible with your template override cart layout.
Compatible with Joomla 2.5/3.x and Virtuemart 2.x - 3.x