I have a requirement to test that a Public Website can serve a defined peak number of 400 page loads per second.
From what I read online, when testing web pages performance, virtual users (threads) should be configured to pause and "think" on each page they visit, in order to simulate the behavior of a real live user before sending a new page load request.
I must use some remote load generator machines to generate this necessary load, and I have a limit on how many virtual users I can use per each load generator. This means that if I make each virtual user pause and "think" for x seconds on each page, that user will not generate a lot of load compared to how much it would if it was executing as fast as it could with no configured think time - and this would cause me to need more users and implicitly need more load generator machines to achieve my desired "page loads per second" and this would be more costly in the end.
If my only request is to prove that a server can serve 400 page loads per second, I would like to know what difference does it really make if I add think times (and therefore use more virtual users) or not.
Why is generally "think time" considered as something which should be added when testing web pages performance ?