It really can vary, depending on the CMS, number of server requests (PHP, SQL, HTTP, etc...), average page size, traffic (average & top),
A small VPS with average specs could do the work for 200K static pages with some text & few images with 10-30K daily traffic,
You'll need a dedicated server if the website is receiving 500K daily traffic, using server-side heavy requests, serving bigger pages, etc...
You'll need to provide more information, make a few tests for the used RAM, CPU, Storage, connection, required GEOs, etc...
Then you'll get more specific & suitable suggestions for your case