If you have a project with a larger number of tasks (IE 900 and above), should you be using 64-bit Microsoft Project (MSP) and the 64-bit Interface instead of 32-bit?
There are no known issues related to the # of tasks and bit level in working with the MSP Integration either bit level is supported. It's recommended to review the below KBs if you are facing performance issues with the MSP Integration:
See also: MSP Integration known issues