damn. out of curiosity, what do u use that much ram for?
Even on the less complicated end, some years ago throwing a shitload of page cache at MongoDB was the only way to maintain high write loads, and eventually one reached a point where one had to keep an entire shard in cache. That bottom end threshold is lower than you think. I don't know if that's changed.
The key here is it's a personal development workstation on which he has these resources. If that's a requirement, I would argue there's something fundamentally wrong with his development processes requiring that much data locally without even a server.