CekuraBench
All comparisons
GoogleGoogle

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.

Last updated Methodology by Dileep Chagam

Compare

Success rate by suite

Higher is better
Appointments59 scenariosMedicare23 scenarios
  • Gemini 3.1 Flash LiveGoogle
    93%
    32%
  • Gemini 3.8 LiveGoogle
    76%
    52%
Each model's share of calls that passed every check, on each suite.
Verdict

Which to pick

Pick Gemini 3.1 Flash Live Preview for reliability across repeated calls (20.7 points higher), calls that pass every check (6.9 points higher), getting the agent's replies right (1.6 points higher) and saving the caller's data correctly (8.8 points higher). Pick Gemini 3.8 Live for fewer stalled calls (1.2 points lower) and fast replies (0.97s sooner). They are level on handling interruptions.

Every metric, side by side

Reliability

Scenarios that passed on all three runs.

Gemini 3.1 Flash Live
62.2%6th
Gemini 3.8 Live
41.5%11th

Gemini 3.1 Flash Live, 20.7 points higher

Success rate

Calls that passed every check.

Gemini 3.1 Flash Live
76.0%5th
Gemini 3.8 Live
69.1%9th

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%6th
Gemini 3.8 Live
94.3%8th

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%5th
Gemini 3.8 Live
70.5%9th

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
2.88s11th
Gemini 3.8 Live
1.91s4th

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

Lower is betterMedianTo p90
Medianp90
  • Gemini 3.8 LiveGoogle
    Gemini 3.8 Live: median 1.91s, p90 2.23s
    1.91s2.23s
  • Gemini 3.1 Flash LiveGoogle
    Gemini 3.1 Flash Live: median 2.88s, p90 4.00s
    2.88s4.00s
2.0s3.0s4.0s
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

  • Reliable on bookings.
All 3 notes on Gemini 3.1 Flash Live
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

  • Replies sooner, and more bookings reach the outcome.
All 3 notes on Gemini 3.8 Live
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.
See the full leaderboardReference agent

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 is more reliable, by 20.7 points. Gemini 3.1 Flash Live Preview passed 51 of 82 scenarios on all three runs, and Gemini 3.8 Live passed 34. A scenario only counts when every run of it passed.

Which should I pick, Gemini 3.1 Flash Live Preview or Gemini 3.8 Live?

For a phone agent, Gemini 3.1 Flash Live Preview, since it gets more scenarios right on every run. 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.

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

Gemini 3.1 Flash Live Preview, by 8.8 points. 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.

Is Gemini 3.1 Flash Live Preview faster than Gemini 3.8 Live?

No. 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 handles interruptions better, Gemini 3.1 Flash Live Preview or Gemini 3.8 Live?

They score the same. Gemini 3.1 Flash Live Preview scores 4.98 and Gemini 3.8 Live 4.98 for how well the agent handled being talked over.

Which goes silent on callers less often, Gemini 3.1 Flash Live Preview or Gemini 3.8 Live?

Gemini 3.8 Live, by 1.2 points. The agent went silent for 10 seconds or more on 3.3% of Gemini 3.1 Flash Live Preview calls and 2.0% of Gemini 3.8 Live calls.

Which is cheaper, 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.

Where does the Gemini 3.1 Flash Live Preview vs Gemini 3.8 Live data come from?

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.