the colored slots indicate were to place the sticks for dual ch mode to work.
when using dual ch memory you must use them in pairs to use them in dual ch mode. running 1 dual ch stick is not dual ch mode. running 2 sticks in different colors is not running in dual ch mode. if you are only using 1 pair you would place 1 of each stick in to the same color slots as dual ch ram works in pairs. if you use say 3 sticks, 1 in an orange slot and 2 in the yellow, the ram will not run in dual ch mode. when using 4 sticks, the ram will run in dual ch mode. please note....when using 4 sticks the ram will NOT operate in quad ch mode as per specs on the board the board must support quad ch's and use quad ch memory to run in quad ch. also the colors vary depending on manufactures.