EPiServer doesnt take much but on the other hand, it's cheaper to add a little more hardware then getting a bunch of support issues.
100 GB Harddrive for blobs and website
Normally they have some virtual environment so processors and cores you can normally just say something like a "modern" frontend server.
No low performance harddrives...
Monitor disk space and CPU automatically.
If higher security is needed, go for a separate server for editors. You can normally scale that one down somewhat...not neccessary for you if you have an intranet I guess.
Something like that?
Is there any hardware requirements/recommendations for EPi 9 on an Windows server 2012?
I have an intranet site with approx. 2000 users (db is on a separate server).