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Gemini 3.1 Flash Live Preview vs Gemini 3.8 Live

Gemini 3.1 Flash Live Preview is ahead on reliability, success rate, agent responses and data accuracy, and Gemini 3.8 Live on stalled calls and response time. The two tie on interruption.

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Success rate by suite

Appointments59 scenariosMedicare23 scenarios

GPT Realtime 2.1OpenAI
92%
81%
GPT-Live 1 + Sol lowOpenAI
97%
49%
Phonic v1Phonic
97%
26%
Gemini 3.8 Live ThinkingGoogle
79%
70%
Grok Think Fast 2.0xAI
96%
25%
Gemini 3.1 Flash LiveGoogle
93%
32%
Gemini 3.8 LiveGoogle
76%
52%
Realtime 2.1 MiniOpenAI
84%
4%
Nova 2 SonicAmazon
80%
6%

Cascade, GPT-4.1Not ranked
97%
83%

Each model's share of calls that passed every check, on each suite.

Every metric, side by side

Reliability

Scenarios that passed on all three runs.

Gemini 3.1 Flash Live: 62.2%5th
Gemini 3.8 Live: 41.5%9th

Gemini 3.1 Flash Live, 20.7 points higher

Success rate

Calls that passed every check.

Gemini 3.1 Flash Live: 76.0%4th
Gemini 3.8 Live: 69.1%7th

Gemini 3.1 Flash Live, 6.9 points higher

Agent responses

Calls where the agent's replies reached the expected outcome.

Gemini 3.1 Flash Live: 95.9%5th
Gemini 3.8 Live: 94.3%6th

Gemini 3.1 Flash Live, 1.6 points higher

Data accuracy

Calls where everything the agent saved matched exactly.

Gemini 3.1 Flash Live: 79.2%4th
Gemini 3.8 Live: 70.5%7th

Gemini 3.1 Flash Live, 8.8 points higher

Stalled calls

Calls where the agent went silent for 10 seconds or more.

Gemini 3.1 Flash Live: 3.3%6th
Gemini 3.8 Live: 2.0%3rd

Gemini 3.8 Live, 1.2 points lower

Interruption

How well it handled being talked over, 0 to 5.

Gemini 3.1 Flash Live: 4.985th
Gemini 3.8 Live: 4.983rd

Level

Response time

Median time to start replying after the caller finishes.

Gemini 3.1 Flash Live: 2.88s9th
Gemini 3.8 Live: 1.91s3rd

Gemini 3.8 Live, 0.97s sooner

Cost / min

One minute of call at the vendor's published rates.

Gemini 3.1 Flash Live: $0.0703rd
Gemini 3.8 Live: No verified rate

Not comparable

The small figure is the place among ranked models. The cascade is not ranked.

Gemini 3.8 Live answers first

Gemini 3.8 Live 1.91s, Gemini 3.1 Flash Live 2.88s at the median.

Response time, median to p90

MedianTo p90

Medianp90

Phonic v1Phonic
Phonic v1: median 1.60s, p90 1.88s
1.60s1.88s
Grok Think Fast 2.0xAI
Grok Think Fast 2.0: median 1.62s, p90 1.94s
1.62s1.94s
Gemini 3.8 LiveGoogle
Gemini 3.8 Live: median 1.91s, p90 2.23s
1.91s2.23s
GPT Realtime 2.1OpenAI
GPT Realtime 2.1: median 1.94s, p90 2.46s
1.94s2.46s
GPT-Live 1 + Sol lowOpenAI
GPT-Live 1 + Sol low: median 2.02s, p90 2.42s
2.02s2.42s
Gemini 3.8 Live ThinkingGoogle
Gemini 3.8 Live Thinking: median 2.07s, p90 2.74s
2.07s2.74s
Realtime 2.1 MiniOpenAI
Realtime 2.1 Mini: median 2.08s, p90 2.75s
2.08s2.75s
Nova 2 SonicAmazon
Nova 2 Sonic: median 2.18s, p90 2.76s
2.18s2.76s
Gemini 3.1 Flash LiveGoogle
Gemini 3.1 Flash Live: median 2.88s, p90 4.00s
2.88s4.00s
Cascade, GPT-4.1Not ranked
Cascade, GPT-4.1: median 2.17s, p90 2.51s
2.17s2.51s

1.5s2.0s2.5s3.0s3.5s4.0s

Seconds from the caller finishing to the agent starting to reply, per model.

What we saw on the calls

Gemini 3.1 Flash Live Preview

Steady on the short form, though it repeats lookups it already made.
On the long form it hands the caller over with the wrong details.
Slowest to reply; after several tool calls its replies fall behind or go missing.
Sometimes says goodbye without hanging up.

Model: models/gemini-3.1-flash-live-preview
Setting: Thinking level high
Voice: Charon
Turn taking: Shared local turn detection
Audio: 16 kHz
Cost: Averaged over the calls with a usage record.

Gemini 3.8 Live

Without extended thinking it replies sooner, and short-form calls reach the outcome more often.
On the long form the conversation still reaches the outcome, but the saved record is wrong far more often.
Weakest of the field when the caller corrects themselves.
Google's turn detection stalls it under background conversation: the caller finishes and no reply comes (AS50, AS52, AS14).
Least predictable of the field.

Model: gemini-3.8-live
Setting: No thinking level
Voice: Charon
Turn taking: Service turn detection
Audio: 16 kHz
Cost: The export carries audio tokens but not text or cached input, so a per-call cost is not derived.

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Related comparisons

Frequently asked questions

Is Gemini 3.1 Flash Live Preview or Gemini 3.8 Live more reliable?

Gemini 3.1 Flash Live Preview passed 51 of 82 scenarios on all three runs, and Gemini 3.8 Live passed 34. Gemini 3.1 Flash Live Preview is ahead, by 20.7 points.

Which saves caller data more accurately, Gemini 3.1 Flash Live Preview or Gemini 3.8 Live?

Gemini 3.1 Flash Live Preview saved everything exactly right on 79.2% of the calls that save data, and Gemini 3.8 Live on 70.5%. On Appointments, 96.5% against 78.4%. On Medicare, 34.8% against 50.0%. A call counts only when nothing is missing, wrong, extra or saved twice.

Which responds faster, Gemini 3.1 Flash Live Preview or Gemini 3.8 Live?

Gemini 3.8 Live starts replying 0.97s sooner at the median. Gemini 3.1 Flash Live Preview takes 2.88s at the median and 4.00s at p90; Gemini 3.8 Live takes 1.91s and 2.23s. Both are measured on the call audio, from the caller finishing to the agent starting to reply.

Which costs less, Gemini 3.1 Flash Live Preview or Gemini 3.8 Live?

There is no verified per-minute rate for Gemini 3.8 Live, so cost cannot be compared yet.

How were Gemini 3.1 Flash Live Preview and Gemini 3.8 Live compared?

Both ran 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, 2,460 calls across the benchmark. A call passes only when the agent said the right things and saved the right data.