Add system requirements section to README

README.md

@@ -7,3 +7,17 @@
 PolicyEngine US is a microsimulation model of the US state and federal tax and benefit system.
 
 To install, run `pip install policyengine-us`.
+
+## System requirements
+
+PolicyEngine-US loads the full US tax-benefit system on import, which requires significant memory. Based on [empirical testing](https://gist.github.com/MaxGhenis/253efeb07f4bfa8b50af768accf73c9d):
+
+| Use case | RAM (minimum) | RAM (recommended) | Typical usage |
+| --- | --- | --- | --- |
+| Household calculations | 8 GB | 16 GB | ~500 MB |
+| Microsimulation (CPS data) | 16 GB | 24-32 GB | 2-4 GB |
+
+Key details:
+- Importing the package loads the tax-benefit system, using ~400 MB
+- Memory scales linearly with multiple simultaneous simulations
+- CPS dataset operations may spike memory during calculations

changelog_entry.yaml

@@ -0,0 +1,4 @@
+- bump: patch
+  changes:
+    added:
+    - Add system requirements section to README documenting memory needs for household calculations and microsimulation.