Grok Voice Think Fast 2.0 is ahead on reliability, success rate, agent responses, data accuracy, stalled calls, response time and cost, and Deepslate Opal on interruption.
Last updated Methodology by Dileep Chagam
Pick Deepslate Opal for handling interruptions (0.04 higher). Pick Grok Voice Think Fast 2.0 for reliability across repeated calls (9.8 points higher), calls that pass every check (6.1 points higher), getting the agent's replies right (0.8 points higher), saving the caller's data correctly (6.3 points higher), fewer stalled calls (0.8 points lower), fast replies (0.65s sooner) and lower cost ($0.032 cheaper).
Scenarios that passed on all three runs.
Grok Think Fast 2.0, 9.8 points higher
Calls that passed every check.
Grok Think Fast 2.0, 6.1 points higher
Calls where the agent's replies reached the expected outcome.
Grok Think Fast 2.0, 0.8 points higher
Calls where everything the agent saved matched exactly.
Grok Think Fast 2.0, 6.3 points higher
Calls where the agent went silent for 10 seconds or more.
Grok Think Fast 2.0, 0.8 points lower
How well it handled being talked over, 0 to 5.
Deepslate Opal, 0.04 higher
Median time to start replying after the caller finishes.
Grok Think Fast 2.0, 0.65s sooner
One minute of call at the vendor's published rates.
Grok Think Fast 2.0, $0.032 cheaper
The small figure is the place among ranked models. The cascade is not ranked.
Grok Think Fast 2.0 1.62s, Deepslate Opal 2.27s at the median.
Grok Voice Think Fast 2.0 is more reliable, by 9.8 points. Deepslate Opal passed 47 of 82 scenarios on all three runs, and Grok Voice Think Fast 2.0 passed 55. A scenario only counts when every run of it passed.
For a phone agent, Grok Voice Think Fast 2.0, since it gets more scenarios right on every run. Grok Voice Think Fast 2.0 is ahead on reliability, success rate, agent responses, data accuracy, stalled calls, response time and cost, and Deepslate Opal on interruption.
Grok Voice Think Fast 2.0, by 6.3 points. Deepslate Opal saved everything exactly right on 72.6% of the calls that save data, and Grok Voice Think Fast 2.0 on 78.9%. On Appointments, 85.4% against 97.1%. On Medicare, 39.4% against 31.8%. A call counts only when nothing is missing, wrong, extra or saved twice.
No. Grok Voice Think Fast 2.0 starts replying 0.65s sooner at the median. Deepslate Opal takes 2.27s at the median and 2.83s at p90; Grok Voice Think Fast 2.0 takes 1.62s and 1.94s. Both are measured on the call audio, from the caller finishing to the agent starting to reply.
Deepslate Opal, by 0.04 on a 0 to 5 scale. Deepslate Opal scores 4.96 and Grok Voice Think Fast 2.0 4.92 for how well the agent handled being talked over.
Grok Voice Think Fast 2.0, by 0.8 points. The agent went silent for 10 seconds or more on 5.3% of Deepslate Opal calls and 4.5% of Grok Voice Think Fast 2.0 calls.
Grok Voice Think Fast 2.0 is $0.032 cheaper a minute. Deepslate Opal costs $0.112 a minute of call and Grok Voice Think Fast 2.0 $0.080, 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.
