The "Perfect AI" was brought up in Look to Windward - the side-discussion in the novel was that cultures typically develop AI that reflect their norms. And the

The "Perfect AI" was brought up in Look to Windward - the side-discussion in the novel was that cultures typically develop AI that reflect their norms. And the AI then interact with the culture over the millennia until they Sublime together. But build an AI without any of those norms, and they Sublime pretty quickly.