Historically Oxford has been much more focused on the rigorous underpinning of CS by Mathematics than other universities, although in recent years they've been cutting down on this and moving closer to the CS syllabus offered by other top-tier universities.
Here's the course list for first year at Oxford:
• Functional Programming
• Design & Analysis of Algorithms
• Imperative Programming I
• Imperative Programming II
• Digital Systems
• Discrete Mathematics
• Logic and Proof
• Linear Algebra
• Calculus
• Probability
Unless you do CS with Mathematics at Cambridge, you'll probably be doing a much less mathematically intensive course.