An application pool can determine the maximum size of virtual memory that a workflow can allocate. This parameter affects the maximum data size that the application object can hold.
If this parameter is not specified (or exceeds 2 GB), then another factor will be whether the process is running in 32-bit mode. If so, you can only expect to get a maximum of 1.5 GB (if it is) in the application, no matter how much memory is present on the server.
On a 64-bit server executing a workflow as a 64-bit process, it will be able to consume as much RAM and a page file that it can receive.
source
share