Magic Cache module can use now?

You can test it, but it's not ready yet.
It helping only on complicating rendering pages, like calendars, etc. if your time of your page load is at least 2sec, if not, don't install yet.
There are many features left (additional engine cache registered in normal way and db proxy cache and some user interface) and some CSS problems.

Closed because Drupal 6 is no longer supported. If the issue verifiably applies to later versions, please reopen with details and update the version.