Definitely not.
Studying in the holidays is to expose yourself to the content and give yourself an inclination the level of personal difficulty that subject poses to you during the year. If you're not naturally good at, say Chemistry, then try and understand the concepts covered in Unit 1/2 before you try and learn the concepts covered in 3/4. Of course, that isn't to say that everything in 1/2 Chem is relevant but much of it is.
I wouldn't get too strung up over doing too much work in the holidays so you can be ahead of the class in all your subjects. Rather, just read through the material you will cover, make sure you concentrate really hard in class, ask your teacher questions after class on concepts you don't understand, discipline yourself to do set work each night and study up for a bit as well. Don't forget to relax on the weekends.
Exactly like EZ said, work efficiently and allocate your efforts into things that'll give you the most benefit. It won't be efficient to mindlessly go through every single question in your Methods textbook all in one sitting. It will be efficient, however, to just choose several of the questions that cover the ideas nicely and leave some for later in the term or such as revision.