Gemini 3.1 Flash Live Preview vs Grok Voice Think Fast 2.0

Gemini 3.1 Flash Live Preview is more reliable, by 5.7 points. Gemini 3.1 Flash Live Preview handled 24 of 70 real callers well on all three runs, and Grok Voice Think Fast 2.0 20. A caller only counts when every run of the call scored 80 or more.

For a voice agent, Gemini 3.1 Flash Live Preview, since it handles more real callers well on every run. Gemini 3.1 Flash Live Preview is ahead on ELO rating, hearing score, turn taking score, task handling score, reliability, calls handled well, calls fully resolved, calls where the agent went quiet and cost, and Grok Voice Think Fast 2.0 on speaking score and median latency.

Gemini 3.1 Flash Live Preview, by 1.9 points higher. Gemini 3.1 Flash Live Preview fully resolved 24.8% of calls and Grok Voice Think Fast 2.0 22.9%. A call counts only when every step the caller needed was done.

No. Grok Voice Think Fast 2.0 starts replying 1.62s sooner at the median. Gemini 3.1 Flash Live Preview takes 3.06s at the median and 3.86s at p90; Grok Voice Think Fast 2.0 takes 1.44s and 1.83s. Both are measured on the call audio, from the caller finishing to the agent starting to reply.

Gemini 3.1 Flash Live Preview, by 1.0 points. The agent went quiet for 10 seconds or more on 7.6% of Gemini 3.1 Flash Live Preview calls and 8.6% of Grok Voice Think Fast 2.0 calls.

Gemini 3.1 Flash Live Preview is $0.010 cheaper a minute. Gemini 3.1 Flash Live Preview costs $0.070 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 with the same prompt, tools and phone connection. Both took the same 70 recorded real human callers on live calls, three times each. Each call is graded on 25 skills across Hearing, Turn Taking, Task Handling and Speaking, and passes at a score of 80 out of 100.