If you have SQL Server 2012 and created a NCCI on a base table partitioned by a computed column, you might have noticed that it produces a serial plan instead of a parallel plan. This, naturally, slows down index creation. How slow depends on your database size and number of partitions.
You can use sys.dm_exec_query_memory_grants DMV to find out the degree of parallelism (dop) as well as required memory. Example output: