Debugging latency in Ollama + OpenWebUI stacks: is the bottleneck the UI or the model?
daddyMaterialBolte · reddit · 2026-08-23
A user is optimizing an internal deployment using NVIDIA Nemotron, Ollama, and OpenWebUI/AnythingLLM, seeing 20 tokens/sec generation with 95% GPU utilization. They suspect the bottleneck lies in the orchestration layer rather than the model itself.
Key questions raised:
- Do interfaces like OpenWebUI add significant latency through prompt construction, RAG, or API overhead?
- How to accurately measure TTFT, prompt processing time, and generation time?
- What methods can systematically benchmark the model directly via Ollama vs. through the UI layer?
- How to verify if the UI is sending larger prompts than visible and measure the impact of context history?
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