According to the documentation for String.replaceAll, it has the following to say about calling the method:
An invocation of this method of the
formstr.replaceAll(regex, repl)
yields exactly the same result as the
expressionPattern.compile(regex).matcher(str).replaceAll(repl)
Therefore, it can be expected the performance between invoking the String.replaceAll, and explicitly creating a Matcher and Pattern should be the same.
Edit
As has been pointed out in the comments, the performance difference being non-existent would be true for a single call to replaceAll from String or Matcher, however, if one needs to perform multiple calls to replaceAll, one would expect it to be beneficial to hold onto a compiled Pattern, so the relatively expensive regular expression pattern compilation does not have to be performed every time.