Sorry if this is old news, but I hadn't realized this before, and I just had an epiphany Last night, and felt I needed to share (and and and and...
)!
Let's say you've managed to max out the Applied Research tech. Now let's say you have just colonized a planet with, oh... let's say... 20 facility slots. Now let's say you want the planet to be dedicated to research, so you order up 20 Research III facilities (let's ignore Computer Complexes and such).
Guess what? Assuming that your planetary construction rate is 2000/2000/2000, you're missing out on 100,000 extra research points at a cost of only 15,000 extra minerals.
Why? Research III facilities cost 2500 minerals to build; you'll build one every other turn. In contrast, Research II facilities cost 2000 minerals; you'll build one each and every turn. By building a new research facility each turn instead of every other turn, you'll be accumulating more research points sooner. The extra 100 points of research generated by a level III facility (compared to a level II facility) does not justify the extra turn necessary to build the level III facility directly. You're better off building level II facilities more quickly, and then upgrading afterwards. This is where the extra 15,000kT of minerals come in: an extra 25,000kT to upgrade the 20 facilities (half of the level III facilities' cost), minus the 10,000kT saved by building cheaper facilities up front.
If your empire production can support the extra expenditure, you should go for it!!!
I just verified this on a spreadsheet this morning. Eeek, a spreadsheet!!! Does that mean I'm helping SEIV turn into MOO3?
--Raynfala