Does anyone know of the performance impacts of doing 1000's of MERGECELL api
calls to ranges in a worksheet??

Basically I am trying to determine the impact of MERGECELL calls because I
have a program that requires ~18000 merges of different cell ranges. It
seems the more times MERGECELL is called the slower it gets over time.

Is there a memory issue in Excel with regards to defining mergeCells?

Thanks for your help