I am a former USACE employee. I have run reasonably large 2-D models on a Precision M6600, but the specs have to be through the roof. I don’t remember what my exact specs were, but the current standard issue machine for science and engineering is the Precision 7760 with a Xeon 11955M, which starts at $5000. Add on a sufficient SSD and RAM and you are easily over $7000.