Creating custom objects in Project & Portfolio Management (PPM) is very slow, particularly when it is created as a subobject to the project object.
Ensure the # of custom attributes for the master object it is associated with is within the recommended range. Anything above 100 can cause performance issues. Excerpt from documentation at: CA PPM Studio Objects and Attributes
Note: The higher the number of attributes on an object, the slower it can take to access or update object related pages as well.
"Important! The product supports up to 500 total attributes for each object. However, we recommend that you do not assign more than 100 attributes to a single custom object. A high number of attributes can result in performance issues and the potential failure of subsequent upgrades. Consider creating a subobject rather than assigning many custom attributes to a single object."