Store the data in the normalized format.
If you are not getting acceptable performance from this scheme, instead of denormalizing, first consider what indexes you have on the table. You're likely missing an index that would make this perform similar to the denormalized table. Next, try writing a query to retrieve data from the normalized table so that the result set looks like the denormalized table, and use that query to create an indexed view. This will give you select performance identical to the denormalized table, but retain the nice data organization benefits of the proper normalization.