### Answer Welcome back! Here are the top practices to improve agent performance and minimize latency with Retell AI: ## Latency Optimization Retell AI achieves 620ms average end-to-end latency [(1) ]() [(2) ]() , which significantly outperforms industry standards [(1) ]() . The platform demonstrates 180ms average time-to-first-token and 140ms average barge-in response . ## Best Practices for Performance 1. Leverage Retell AI's Proprietary LLM Retell AI's proprietary low-latency LLM is fine-tuned for voice interactions with sub-800ms end-to-end latency . 2. Use Comprehensive Testing Methods - LLM Playground for rapid iteration and debugging [(3) ]() - LLM Simulation Testing for batch testing and regression validation - Web/Phone Call Testing for real-world voice quality validation 3. Optimize Turn-Taking Retell AI's latest turn-taking model enhancements reduce false interruptions while maintaining responsive barge-in capabilities [(1) ]() . The system better distinguishes between natural speech pauses and actual conversation turns . 4. Implement Warm Transfer 2.0 Released July 7, 2025, Warm Transfer 2.0 reduces handoff latency by 40% through pre-established connection pools and context pre-loading . 5. Use Structured Handoffs Deliver structured context at handoff to reduce agent talk time and after-call work [(4) ]() . 6. Minimize Dialog Turns Use targeted follow-ups instead of broad open-ended q

uestions to reduce clarification loops . 7. Leverage Edge Deployment Retell AI's distributed processing reduces geographic latency [(1) ]() . 8. Implement Streaming Optimization Chunked audio processing minimizes buffering delays . 9. Use Predictive Pre-Loading Context anticipation reduces response preparation time . 10. Apply Adaptive Bitrate Dynamic quality adjustment maintains performance under network stress . ## Testing Workflow Recommendation Follow this phased approach [(3) ]() : - **Phase 1 (Development) **: Use LLM Playground for prompt iteration - **Phase 2 (QA) **: Run LLM Simulation Testing for regression tests - **Phase 3 (Production Validation) **: Conduct Web/Phone Call Testing - **Phase 4 (Continuous) **: Set up automated test suites ## Turn-Taking Considerations If you experience higher end-to-end latency, it could be related to turn-taking behavior when interactions aren't standard [(5) ]() . The system waits for natural conversation pauses, which is counted in E2E latency .

​ To learn more, see the sources I considered: [[1] ](https://www.retellai.com/resources/ai-voice-agent-latency-face-off-2025) [[2] ](https://www.retellai.com/resources/2025-best-voice-ai-companies-call-center-automation) [[3] Testing Overview](https://docs.retellai.com/test/test-overview) [[4] 9 Best Voice AI Agents for Reducing Average Handle Time in 2026 | Retell AI](https://www.retellai.com/blog/best-voice-ai-agents-for-reducing-average-handle-time) [[5] High end to end latency in phone calls](https://discord.com/channels/1186424376300679209/1450956304288845855) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Retell AI's proprietary LLM is their low-latency Large Language Model that's fine-tuned specifically for voice interactions [(1) ]() . This is the "Retell LLM" option you'll find when configuring your agent's response engine. You can access it when creating or editing an agent in the Retell AI dashboard. When setting up your agent, you'll see model options that include the Retell LLM alongside other choices like GPT-4 series, Claude, and Gemini . The Retell LLM delivers sub-800ms end-to-end latency and is optimized for concise replies and reliable function calls . It's designed to minimize hallucinations while maintaining natural conversation flow. To use it, simply select "Retell LLM" as your model choice in the agent configuration settings. This is different from integrating your own custom LLM via websocket [(2) ]() , which would require additional setup.

​ To learn more, see the sources I considered: [[1] Why Low Latency Matters for AI Agents | Retell AI](https://www.retellai.com/blog/why-low-latency-matters-how-retell-ai-outpaces-traditional-players) [[2] Integrate LLM](https://docs.retellai.com/integrate-llm/integrate-llm) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.