CekuraBench

Grok Voice Think Fast 2.0

Every modelCompare

67.1%

Reliability

6th of 12

1.62s

Median reply

3rd of 12

$0.080

Cost / min

5th of 9

Reliability vs. response time

Higher and further left is better

Best quadrant
Reliability, pass³ (%)
Median response time (s)

For the wider field, see our pick of the best voice AI APIs for real-time audio.

Grok Voice Think Fast 2.0 against every other model

Scenarios that passed on all 3 runs, pass³. Higher is better.

#ModelReliability
  1. 01Grok Voice 3.081.7%
  2. 02GPT Realtime 2.179.3%
  3. 03GPT-Live 1 + GPT-6 Sol75.6%
  4. 04Azure Realtime70.7%
  5. 05Phonic v168.3%
  6. 06Grok Voice Think Fast 2.067.1%
  7. 07Gemini 3.1 Flash Live Preview62.2%
  8. 08Deepslate Opal57.3%
  9. 09Gemini 3.8 Live Extended Thinking52.4%
  10. 10Amazon Nova 2 Sonic50.0%
  11. 11GPT Realtime 2.1 Mini50.0%
  12. 12Gemini 3.8 Live41.5%
  • refCascade82.9%

Where Grok Voice Think Fast 2.0 struggled

Grok Voice Think Fast 2.0 falls furthest behind on Medicare compliance and routing: 25% passed, against a median of 40%.

Below the medianPassedMedian
  • Medicare compliance & routing
    25%median 40%
  • Caller corrects or changes mind
    71%median 81%
  • Interruptions & barge-in
    80%median 90%
Mistakes in saved data
  • Wrong value70 · 43%
  • Field left out38 · 24%
  • Extra call18 · 11%

Fields it got wrong most: lead_id, route_id, consent_id

Response time at P50, P90 and P95

Grok Voice Think Fast 2.0 starts replying in 1.62s on a typical turn and 1.99s on the slowest turn in twenty, 3rd fastest of 12 at the median.

ModelP50P90P95
  • Cascade
    2.17s2.51s2.62s
Seconds from the caller finishing to the agent replying. The bar is the typical turn, P50.

Grok Voice Think Fast 2.0 head to head

Every comparisonAll 12 models

How much audio Grok Voice Think Fast 2.0 was tested on

246 live calls: 82 scenarios, each run three times. The median call ran 1:43.

Live calls
246
Scenarios
82
Booking calls
177
Medicare calls
69
Replies per call
10.7
Median call
1:43

82 scenarios, the same for every model. See every test case

Grok Voice Think Fast 2.0 FAQ

  • Grok Voice Think Fast 2.0 passed 55 of 82 scenarios on all three runs, 67.1%, 6th of 12 realtime models. Across all 246 calls, 76.0% passed every check.

  • Grok Voice Think Fast 2.0 starts replying 1.62s after the caller finishes at the median, 1.94s at P90 and 1.99s at P95. That is 3rd fastest of 12 at the median, measured on the call audio.

  • Grok Voice Think Fast 2.0 falls furthest behind the field on Medicare compliance and routing: 25% of calls passed, against a median of 40%. When it saved data wrong, the most common mistake was wrong value, 43% of them.

  • Grok Voice Think Fast 2.0 saved everything exactly right on 78.9% of the calls that save data, 7th of 12. On Booking calls, 97.1%. On Medicare calls, 31.8%.

  • $0.080 a minute of call at xAI's published rates, 5th cheapest of 9 priced models. Excludes a text-input charge the vendor lists without a unit.

  • Cekura ran Grok Voice Think Fast 2.0 as the whole agent in the same open-source Pipecat pipeline as every other model, with the same prompt, tools and connection. A simulated caller worked through 82 scenarios on live calls, three times each: 246 calls for Grok Voice Think Fast 2.0. A call passes only when the agent said the right things and saved the right data.