I think making some sort of notes is always good, and it doesn't have to be paragraphs and paragraphs of information, it can just be by dot points if you want. The reason being when one revises over their notes and add more information, they are consolidating that information into their long term memory. Of course you can test the information you remembered by doing past papers and CHECKING your answer with the SAMPLE ANSWER, but if you happen to learn anything in the new answer, you will not be able to remember it a year later if you don't write it down. If notes doesn't work, maybe do a mind map to link the concepts together. Although you may be able to answer it dot point by dot point, a lot of the harder-and higher mark exam questions involves a synthesis of different dot points into the one question, sometimes from across different modules as well, such as in the 2012 HSC chemistry, where there was a question combining battery/cells from topic 1 and the need for scientist to collaborate from topic 3. If you don't make some sort of connection between the information-i.e. by writing notes, otherwise all the concepts will likely to be isolated and you will find it difficult to answer the higher mark questions.
Without making notes, it is quite difficult to remember all your practicals as well as any relevant visual diagrams over the year, and if you just read over textbooks-you will actually be absorbing a lot of irrelevant information, and don't remember the relevant things in the depth required. Basically, almost most of the dot points of the syllabus can be expanded through combining with other dot points to become a 6/7 mark question-will you be confident enough to answer in such detail for every single dot point, remembering all the chemical equations, diagrams and definitions as well as concise conceptual definition?
I personally find learning content ahead in the holidays is SECOND PRORITY, the FIRST PRIORITY is to consolidate what you have learnt. There was something you missed that is very important when answering the question 'explain the process of fermentation'-that is, you must be providing the relevant chemical equation as well as stating the optimal conditions under which fermentation occurs-this is vital. I think you will see although you may remember some of the information, it is impossible to remember all of the ESSENTIAL INFORMATION without notes.
Ultimately, most people will try to write notes, practise exam questions and learn new content in the holidays(the studious ones), and you will see time and time again that state rankers make their own notes, and most people make some sort of notes or buy a set of notes to revise. So notes are important-whether you make an audio summary and listen it over and over again, whether you prepare a sort of written summary-mind maps and what not, and try to explain the entire syllabus to someone. But regardless, hope this helps and whatever study methods you adopt, I truly wish you all the best for your HSC studies