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GPT-Live 1 + GPT-6 Sol (low thinking) vs GPT Realtime 2.1

GPT Realtime 2.1 is ahead on reliability, success rate, data accuracy, stalled calls, interruption and response time, and GPT-Live 1 + GPT-6 Sol (low thinking) on agent responses and cost.

Last updated Methodology by Dileep Chagam

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Success rate by suite

Higher is better
Appointments59 scenariosMedicare23 scenarios
  • GPT Realtime 2.1OpenAI
    92%
    81%
  • GPT-Live 1 + Sol lowOpenAI
    97%
    49%
Each model's share of calls that passed every check, on each suite.
Verdict

Which to pick

Pick GPT-Live 1 + GPT-6 Sol (low thinking) for getting the agent's replies right (0.8 points higher) and lower cost ($0.030 cheaper). Pick GPT Realtime 2.1 for reliability across repeated calls (3.7 points higher), calls that pass every check (5.3 points higher), saving the caller's data correctly (3.0 points higher), fewer stalled calls (8.9 points lower), handling interruptions (0.09 higher) and fast replies (0.08s sooner).

Every metric, side by side

Reliability

Scenarios that passed on all three runs.

GPT-Live 1 + Sol low
75.6%2nd
GPT Realtime 2.1
79.3%1st

GPT Realtime 2.1, 3.7 points higher

Success rate

Calls that passed every check.

GPT-Live 1 + Sol low
83.7%3rd
GPT Realtime 2.1
89.0%1st

GPT Realtime 2.1, 5.3 points higher

Agent responses

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

GPT-Live 1 + Sol low
100.0%1st
GPT Realtime 2.1
99.2%2nd

GPT-Live 1 + Sol low, 0.8 points higher

Data accuracy

Calls where everything the agent saved matched exactly.

GPT-Live 1 + Sol low
89.0%2nd
GPT Realtime 2.1
92.0%1st

GPT Realtime 2.1, 3.0 points higher

Stalled calls

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

GPT-Live 1 + Sol low
12.2%11th
GPT Realtime 2.1
3.3%5th

GPT Realtime 2.1, 8.9 points lower

Interruption

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

GPT-Live 1 + Sol low
4.8910th
GPT Realtime 2.1
4.984th

GPT Realtime 2.1, 0.09 higher

Response time

Median time to start replying after the caller finishes.

GPT-Live 1 + Sol low
2.02s6th
GPT Realtime 2.1
1.94s5th

GPT Realtime 2.1, 0.08s sooner

Cost / min

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

GPT-Live 1 + Sol low
$0.0552nd
GPT Realtime 2.1
$0.0856th

GPT-Live 1 + Sol low, $0.030 cheaper

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

GPT Realtime 2.1 answers first

GPT Realtime 2.1 1.94s, GPT-Live 1 + Sol low 2.02s at the median.

Response time, median to p90

Lower is betterMedianTo p90
Medianp90
  • 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
1.5s2.5s
Seconds from the caller finishing to the agent starting to reply, per model.

What we saw on the calls

GPT-Live 1 + GPT-6 Sol (low thinking)

  • Near perfect on bookings, run after run.
All 4 notes on GPT-Live 1 + Sol low
Model
gpt-live-1
Setting
Delegates reasoning and tools to Sol
Voice
marin
Turn taking
Service turn detection
Audio
24 kHz
Cost
Includes the delegated backend model.

GPT Realtime 2.1

  • Almost never fails, and rarely twice in a row.
All 4 notes on GPT Realtime 2.1
Model
gpt-realtime-2.1
Setting
Reasoning high
Voice
marin
Turn taking
Service turn detection
Audio
24 kHz
Cost
Excludes caller transcription, which the service does not meter per call.
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Frequently asked questions

Is GPT-Live 1 + GPT-6 Sol (low thinking) or GPT Realtime 2.1 more reliable?

GPT Realtime 2.1 is more reliable, by 3.7 points. GPT-Live 1 + GPT-6 Sol (low thinking) passed 62 of 82 scenarios on all three runs, and GPT Realtime 2.1 passed 65. A scenario only counts when every run of it passed.

Which should I pick, GPT-Live 1 + GPT-6 Sol (low thinking) or GPT Realtime 2.1?

For a phone agent, GPT Realtime 2.1, since it gets more scenarios right on every run. GPT Realtime 2.1 is ahead on reliability, success rate, data accuracy, stalled calls, interruption and response time, and GPT-Live 1 + GPT-6 Sol (low thinking) on agent responses and cost.

Which saves caller data more accurately, GPT-Live 1 + GPT-6 Sol (low thinking) or GPT Realtime 2.1?

GPT Realtime 2.1, by 3.0 points. GPT-Live 1 + GPT-6 Sol (low thinking) saved everything exactly right on 89.0% of the calls that save data, and GPT Realtime 2.1 on 92.0%. On Appointments, 100.0% against 95.9%. On Medicare, 60.6% against 81.8%. A call counts only when nothing is missing, wrong, extra or saved twice.

Is GPT-Live 1 + GPT-6 Sol (low thinking) faster than GPT Realtime 2.1?

No. GPT Realtime 2.1 starts replying 0.08s sooner at the median. GPT-Live 1 + GPT-6 Sol (low thinking) takes 2.02s at the median and 2.42s at p90; GPT Realtime 2.1 takes 1.94s and 2.46s. Both are measured on the call audio, from the caller finishing to the agent starting to reply.

Which handles interruptions better, GPT-Live 1 + GPT-6 Sol (low thinking) or GPT Realtime 2.1?

GPT Realtime 2.1, by 0.09 on a 0 to 5 scale. GPT-Live 1 + GPT-6 Sol (low thinking) scores 4.89 and GPT Realtime 2.1 4.98 for how well the agent handled being talked over.

Which goes silent on callers less often, GPT-Live 1 + GPT-6 Sol (low thinking) or GPT Realtime 2.1?

GPT Realtime 2.1, by 8.9 points. The agent went silent for 10 seconds or more on 12.2% of GPT-Live 1 + GPT-6 Sol (low thinking) calls and 3.3% of GPT Realtime 2.1 calls.

Which is cheaper, GPT-Live 1 + GPT-6 Sol (low thinking) or GPT Realtime 2.1?

GPT-Live 1 + GPT-6 Sol (low thinking) is $0.030 cheaper a minute. GPT-Live 1 + GPT-6 Sol (low thinking) costs $0.055 a minute of call and GPT Realtime 2.1 $0.085, at each vendor's published rates.

Where does the GPT-Live 1 + GPT-6 Sol (low thinking) vs GPT Realtime 2.1 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.