Model comparison
Compare Gemini 3.8 Live Extended Thinking and Grok Voice Think Fast 2.0 using the same provider-sourced voice & realtime rubric. No mystery score and no invented benchmark ranking.
Quick take
A separate Gemini voice model that works through complex requests in the background while keeping the conversation going.
Integration differs from standard Live: tools must be asynchronous, and the app must track interaction_status. A finished utterance does not mean the background task has finished.
SpaceXAI's current realtime speech-to-speech model for sub-second conversational agents with tool access.
The model-specific price is higher than the generic 'starting at' Voice API headline. Use the Think Fast 2.0 row when budgeting.
Compare the published facts
Values use each provider's own published units and limits. A blank means the provider did not publish a directly comparable value in the sources reviewed.
| Voice & realtime | Gemini 3.8 Live Extended Thinking | Grok Voice Think Fast 2.0 |
|---|---|---|
| Price basisToken-, character-, or minute-based price for the listed access route. | Audio $0.005/min in · $0.018/min out | $0.08 / audio minute |
| Interaction modeSpeech-to-speech, audio-to-audio, or streamed text-to-speech behavior. | Speech-to-speech with visual input and background reasoning | Realtime speech-to-speech with tools |
| Published latencyProvider-published measurement with its stated exclusions; not a Cody test. | Not published | Sub-second provider claim |
| LanguagesProvider-documented language coverage or a clear unpublished marker. | Multilingual; verify current Live API support | Exact supported list not published here |
| Tools & controlNative function calling, reasoning, or speech-control features. | Async functions only, search grounding | Realtime tool use |
| Context or input limitDocumented token or character limit where it is meaningful. | 131,072 input · 65,536 output | Not published |
How to choose
Start with the job you need to complete, then validate cost, access, and policy details on your exact provider route.
Google says paid Gemini API prompts and responses are not used to improve its products. Unpaid-service content generally may be used, with different treatment for EEA, UK, and Swiss users; check the current terms for your account and region.
Provider and API links
SpaceXAI says it does not train on API inputs or outputs without explicit permission. Default encrypted retention is 30 days; team-level zero data retention is available with feature tradeoffs.
Provider and API links
Frequently asked questions
Gemini 3.8 Live Extended Thinking: A separate Gemini voice model that works through complex requests in the background while keeping the conversation going. Grok Voice Think Fast 2.0: SpaceXAI's current realtime speech-to-speech model for sub-second conversational agents with tool access.
Consider Gemini 3.8 Live Extended Thinking when your priority is Multi-step voice support workflows. Consider Grok Voice Think Fast 2.0 when your priority is Realtime voice agents with tools. Test both with your own data and provider route before committing.
No. This comparison aligns provider-published facts for the Voice & realtime category. It does not claim a universal winner or combine incompatible third-party benchmark scores.
