It depends on your occupation how long processing will take. This is from their website:
The changes to priority processing arrangements address the needs of industry by targeting skills in demand across a number of sectors, while ensuring that the Skilled Migration Programme is responsive to the current economic climate and the needs of the Australian economy.
Priority processing arrangements are subject to changes in response to Australia’s economic situation and do not change visa eligibility criteria.
Priority processing arrangements apply to current applications, including those in the final stages of processing. Departmental case officers must follow the direction made by the minister about priority processing and cannot process applications outside of the set order.