Change the cost threshold of parallelism

The cost threshold of parallelism determines which queries are candidates for parallel execution. This property’s default value is 5, which means that the optimizer switches to a parallel plan if the cost of a serial plan is more than 5 (which refers to an abstracted unit of cost, not estimated time). We recommend that you set this property to a higher number.

The default value was appropriate back when processors had high price tags, processing power was low, and query processing was slower than it is now. Processors today are much faster. As a result, comparatively smaller queries (for example, given a cost threshold of 32) won’t benefit a lot from parallel execution, especially given the overhead associated with coordinating parallel execution.

In most cases, a cost threshold of parallelism setting of 50 is a good starting point. Here's an example of how to configure the cost threshold of parallelism:

USE sampledb;  
GO  
EXEC sp_configure 'show advanced options', 1 ;  
GO  
RECONFIGURE  
GO  
EXEC sp_configure 'cost threshold for parallelism', 50 ;  
GO  
RECONFIGURE  
GO