ok, when i last tested my map, it went VERY slow
i rode it is because i never caulked anything. My brushes have all texture around
so i understand i have to caulk the sides that can’t be viewn by the player
only problem, i found nowhere where how i have to select 1 side of a brush :S
if i press shift mouse 1, it selects everything
how can i select a part from a brush?
I suggest you completely caulk your brushes, then use CTRL + SHIFT + LMB to select one or more sides of your brushes for texturing then.
you completely caulk your brushes
That s an awful thing to do, because its a HELLOFALOTOFWORK to get the things textured again.
I dont think its necessary either, because I d at the VERY first want a look at the vis-blocking of the map.
What is your hardware specs and how much FPS do u get in your map?
Which are your compile settings?
Can you plz post the part of yoru compile logfile that does the VIS-compiling?
Then, you might want to run around in your map using r_speeds and r_showtris 2. Have a search on this forum on r_showtris 2, what it does, and what it means for mapping.
Caulking everything should be the very last thing, and when you ve done all the other things to improve game performance, you won’t need caulking anymore.
Dunno what version your running, but In Radiant 1.4 it’s “Shift+Alt” to select faces. If you select all the brushes(fully), then deselect the faces you want to keep, you can caulk the rest withouth having to redo everything. 
I like the re-do technique as it will caulk all unseen faces and will show you if the brush is actually visible at all.
This seems most natural, as I allso use this when I’m building new brushes.
It’s best to use caulk as your default texture then do the earlier suggestion of CTRL+SHIFT+LMB. Plan your work. It will save you lots of time.