[Gene_Parmesan]

I would say first, that's the power of exponential complexity. Second, AI in games tends to consist of somewhat complicated goal-based & fuzzy logic behaviors. Third, game AI agents have interactions that take place within a 3d world that has to be modeled accurately. That means lots of expensive computations for things like line of sight, pathfinding, and so on. Finally, given that games are soft real-time and include remarkably expensive 3D rendering, the compute budget available for AI functions I would guess would be somewhere around the order of 2ms per frame (on a 16.7 ms frame, for 60fps).

Though, two through four can usually be handled without issue, provided the devs know what they're doing & architect the engine correctly. (edit: And keep the scope in check, which ultimately is the responsibility of the leadership.) Unfortunately, this appears to be where #1 messed things up for them.

[KptMarchewa]

You don't really need to rerun your AI logic every frame though. It's more than enough if you do it every ~second, and can compute it on a separate thread.

[hutzlibu]

That depends on the type of game. The game I am working on would not work with a AI update every second.