There's nothing in SQL Server 2012 that is inherently worse about deadlocks than previous versions of SQL Server. So, the things that are different might be the issue. The query optimizer in SQL Server 2012 is different. That means that queries that might have run adequately on previous versions of SQL Server could experience slower performance on 2012. But, that's almost always the case when looking at queries that were slow performers in those other versions of SQL Server too. They just performed well enough. Deadlocks are fundamentally a performance problem. So, the answer is to go through all the proper steps to ensure your queries are well-constructed, you have proper indexing in place, your statistics are up to date, and all the rest.