Drow don't plot and scheme to kill each other just to kill each other.. they plot and scheme to kill each other to get ahead in Drow society. They pick someone above them who has exposed an opening, and they strike.. sometimes planning for years for the opportunity. Survival of the Drow still trumps that personal ambition, owing to their origin as the 'abandoned' Elves forced to survive in the hostile, lightness Darklands.
At this point, Second Darkness contains the definitive canonical information on Drow (in the support article "Drow of Golarion"). There is some additional information in "Into the Darklands".
Some minor detaila may have changd from 3.5 to Pathfinder (Elves in 3.5 did not sleep; Pathfinder Elves do, for example), but for the most part the 3.5-era content remains the core. Some mechanics have been re-visited and expanded (Fleshwarps and Fleshcrafts in Inner Sea Magic, and the Pain Taster class in Occult Mysteries, as examples).
The Second Darkness AP used some mechanical materials from Green Ronin's "Plot & Poison" (a sourcebook on Drow), which was revised to be the "Advanced Race Codex: Drow" for 3.5 (PDF only as far as I know), but I don't think any cultural material was used.
Wayfinder #9 has some interesting material on Drow and Duergar.
EDIT: Fixed name of Green Ronin product, and added reference to Wayfinder #9