xAI 发布 Grok Voice Think Fast 2.0 语音模型，定价 $0.08/分钟

Today, we're announcing Grok Voice Think Fast 2.0, our next-generation voice model with improved intelligence, transcription accuracy, and conversational capabilities.

Speech-to-speech benchmark comparison between Grok Voice Think Fast 2.0 and competing models, per Artificial Analysis.
Benchmark	Grok Voice Think Fast 2.0 (this release)	Grok Voice Think Fast 1.0	GPT-Realtime-2.1 (High)	Gemini 3.1 Flash (High)
Overall AA Speech-to-Speech Quality Index	82.9%	75.7%	79.1%	69.5%
Speech Reasoning Big Bench Audio	97.2%	97.1%	96.0%	96.6%
Conversational Dynamics Full Duplex Bench	95.1%	77.8%	95.7%	74.3%
Agentic Performance τ-voice Bench	56.5%	52.1%	45.7%	37.7%
Speed Time to First Audio	0.70s	1.25s	—	2.98s

Grok Voice Think Fast 2.0 outperforms even dedicated, state of the art transcription models when it comes to accuracy. In our evaluation across thousands of short phrases in 24 different languages, we've demonstrated a 1.5–2.0× improvement relative to Deepgram Nova 3 and ElevenLabs Scribe v2, and a 1.4× improvement relative to Grok Voice Think Fast 1.0.

The gap between Grok Voice Think Fast 2.0 and dedicated speech-to-text models widens to ~10× in noisy settings. We've focused on making Grok Voice Think Fast 2.0 perform exceptionally well in real-world settings, with substantial background noise and telephony compression.

Transcription accuracy

Word Error Rate (%). Lower is better.

Grok Voice Think Fast 2.0

Grok Voice Think Fast 1.0

Deepgram Nova 3

ElevenLabs Scribe v2

Reasoning Efficiency

Grok Voice Think Fast models have a unique characteristic: they reason through queries while speaking. Reasoning in parallel with speech makes the model substantially smarter than other speech-to-speech models with no impact on latency.

Grok Voice Think Fast 2.0 has been trained to be very efficient with reasoning tokens relative to its predecessor. In production settings, this means that tool calls are snappier, usually executing before the end of the agent's first sentence.

Reasoning efficiency

Relative reasoning tokens per response (P50). Lower is better.

Grok Voice Think Fast 2.0

0.4×

Grok Voice Think Fast 1.0

1.0×

Conversational Capability

We've trained Grok Voice Think Fast 2.0 to be a better conversationalist. By using extensive reinforcement learning to push the model towards patterns we see in real human conversation, we've found that broadly the model speaks in shorter sentences, asks one question at a time, and avoids fluff. From the user's perspective, conversations with the agent are simple and fluid, even though the model is often guiding the conversation through complex workflows and thinking several steps ahead behind the scenes.

Migration & Pricing

Grok Voice Think Fast 2.0 is expected to result in improved performance across almost all use cases without any edits to existing prompts. In A/B testing this model on Starlink (+1 888 GO STARLINK), we've seen a significant increase in sales conversion rate and support containment rate.

On August 5, 2026, grok-voice-latest will move from grok-voice-think-fast-1.0 to grok-voice-think-fast-2.0. No action needed to upgrade. To stay on Grok Voice Think Fast 1.0, pin grok-voice-think-fast-1.0 before then.

We believe pricing should be predictable and transparent. Grok Voice Think Fast 2.0 is priced at $0.08 / min of audio.

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