I had tested a while back BE 2.5 with
XML VS SQL had about 100 posts testing and seems to make no difference loading wise.
You can give it a try yourself and see.
BE throws everything up in to the app_pool anyway so which data provider being use as far as I know has no "performance" issues after initial boot.
What really matters is how much the server have in terms of memory for the app_pool is what can effect loading times.
If the server don't have much memory and has to keep reloading the app_pool that can make it slower.
I had heard that over 1,000 or so users from an Admin point of view SQL would be better.
"PostView" Not sure what you mean by that you mean the List View where on default page lists a certain amount of posts?
How many posts and views it would take to slow down the system depends on the hardware of the server and the network it is on.
If server has alot of resources and a good network would take a lot to slow down the system, but it really depends on the server / network side and
When getting hits in the 3,000 or more per hour range would need a private server share hosting won't do.
Also would need way more bandwidth to handle the visits.
Maybe some day will do another test of
XML vs SQL :)
I am always curious about this too.
This time would test 500 posts.