I have performed a small test for d6, here is the results, I'll suggest others to post there test report with different combination n modules(specially with cck, views and panels), to help core team get more data for optimisation.
I have created 5 users, 2 vocabs with 5 terms, 200 content (page/story) and 700 comments via devel module.
modules enabled- default installation+path+devel+search
Search index :100%
s/w Platform: winxp with xamp1.6.3a
h/w palteform: Fujitsu 915gm laptop with Celeron M 1.5 Ghz and 512 Ram.
I'm running single site, there is no other load on machine.
Loading /node page :Executed 100 queries in 306.88 milliseconds
Loading modules page :Executed 81 queries in 200.77 milliseconds. (it will grow with no of modules, i think)
Loading search result page :Executed 173 queries in 856.25 milliseconds.
Loading users list page : Executed 79 queries in 451.58 milliseconds
Loading content list page :Executed 265 queries in 857.25
Loading blocks list page :Executed 132 queries in 1126.82 milliseconds
Loading url alies list page : Executed 204 queries in 715.69 milliseconds
Loading recent logs page : Executed 156 queries in 655.38 milliseconds.
I suggest others to also post there test report with different combination n modules(specially with cck, views and panels), to help core team get more data for optimisation.