How does too many nodes in a process model increase memory footprint?

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How to Create Memory Efficient Models

Also as a simple answer I would say, More the number of nodes more the memory allocation to run the models efficiently. Your instances will consume more memory to keep up with the audit details such as your variable history or any other data logs. So smaller the model (Lesser nodes) better the performance. Converting your long models into smaller chunks and running them based on their priority as synchronous/asynchronous.

Have you got a chance to look at this article?

How to Create Memory Efficient Models

Also as a simple answer I would say, More the number of nodes more the memory allocation to run the models efficiently. Your instances will consume more memory to keep up with the audit details such as your variable history or any other data logs. So smaller the model (Lesser nodes) better the performance. Converting your long models into smaller chunks and running them based on their priority as synchronous/asynchronous.