Phonic v1 is ahead on reliability, success rate, agent responses, stalled calls and response time, and Grok Voice Think Fast 2.0 on data accuracy, interruption and cost.
Last updated Methodology by Dileep Chagam
Pick Grok Voice Think Fast 2.0 for saving the caller's data correctly (1.5 points higher), handling interruptions (0.03 higher) and lower cost ($0.060 cheaper). Pick Phonic v1 for reliability across repeated calls (1.2 points higher), calls that pass every check (1.2 points higher), getting the agent's replies right (1.2 points higher), fewer stalled calls (4.5 points lower) and fast replies (0.02s sooner).
Scenarios that passed on all three runs.
Phonic v1, 1.2 points higher
Calls that passed every check.
Phonic v1, 1.2 points higher
Calls where the agent's replies reached the expected outcome.
Phonic v1, 1.2 points higher
Calls where everything the agent saved matched exactly.
Grok Think Fast 2.0, 1.5 points higher
Calls where the agent went silent for 10 seconds or more.
Phonic v1, 4.5 points lower
How well it handled being talked over, 0 to 5.
Grok Think Fast 2.0, 0.03 higher
Median time to start replying after the caller finishes.
Phonic v1, 0.02s sooner
One minute of call at the vendor's published rates.
Grok Think Fast 2.0, $0.060 cheaper
The small figure is the place among ranked models. The cascade is not ranked.
Phonic v1 1.60s, Grok Think Fast 2.0 1.62s at the median.
Phonic v1 is more reliable, by 1.2 points. Grok Voice Think Fast 2.0 passed 55 of 82 scenarios on all three runs, and Phonic v1 passed 56. A scenario only counts when every run of it passed.
For a phone agent, Phonic v1, since it gets more scenarios right on every run. Phonic v1 is ahead on reliability, success rate, agent responses, stalled calls and response time, and Grok Voice Think Fast 2.0 on data accuracy, interruption and cost.
Grok Voice Think Fast 2.0, by 1.5 points. Grok Voice Think Fast 2.0 saved everything exactly right on 78.9% of the calls that save data, and Phonic v1 on 77.4%. On Appointments, 97.1% against 98.2%. On Medicare, 31.8% against 25.0%. A call counts only when nothing is missing, wrong, extra or saved twice.
No. Phonic v1 starts replying 0.02s sooner at the median. Grok Voice Think Fast 2.0 takes 1.62s at the median and 1.94s at p90; Phonic v1 takes 1.60s and 1.88s. Both are measured on the call audio, from the caller finishing to the agent starting to reply.
Grok Voice Think Fast 2.0, by 0.03 on a 0 to 5 scale. Grok Voice Think Fast 2.0 scores 4.92 and Phonic v1 4.89 for how well the agent handled being talked over.
Phonic v1, by 4.5 points. The agent went silent for 10 seconds or more on 4.5% of Grok Voice Think Fast 2.0 calls and 0.0% of Phonic v1 calls.
Grok Voice Think Fast 2.0 is $0.060 cheaper a minute. Grok Voice Think Fast 2.0 costs $0.080 a minute of call and Phonic v1 $0.140, at each vendor's published rates.
Cekura ran both as the whole agent in the same open-source Pipecat pipeline, with the same prompt, tools and connection. A simulated caller worked through all 82 scenarios on live calls, three times each, 2,952 calls across the benchmark. A call passes only when the agent said the right things and saved the right data.
