CURRENT MODEL COMPARISON / 2026

GPT-6.1 Sol vs Gemini 3.8 Flash

How do the latest Sol and Flash editions behave in a software-engineering agent?

Reviewed Live model evidence ↗
OpenAI

GPT-6.1 Sol↗

A September 2026 release for complex coding and professional work, available through Responses and Chat Completions.

Access type
Hosted API
Original release date
Model ID
gpt-6.1-sol
API formats
Responses and Chat Completions
Latest lifecycle note
Ultrafast mode added to Responses on October 8, 2026
License / terms
Provider service terms

OpenAI directs tool-calling workflows to the Responses API. Record the service tier and reasoning setting; Ultrafast mode was added on October 8, 2026.

Official source ↗Latest artifacts and release journal →
Google

Gemini 3.8 Flash↗

A September 2026 generally available Gemini release for software engineering, agents and enterprise workflows.

Access type
Hosted API
Original release date
Model ID
gemini-3.8-flash
Source focus
Software engineering, autonomous agents and enterprise workflows
License / terms
Provider service terms

The provider announcement describes intended uses, not an independent result in your application. Check accepted inputs, thinking controls and current pricing on the selected Gemini endpoint.

Official source ↗Latest artifacts and release journal →

The decision to test

Keep the task, tools and success criteria fixed while preserving each provider's native request format. GPT-6.1 Sol launched September 29, 2026; Gemini 3.8 Flash became generally available September 2. Provider descriptions are a starting hypothesis for an application test.

Measure completion, not a convincing first answer

Use issues that require reading files, editing code and running tests. Record abandoned tasks, failed tools and patches that break existing tests. A plausible plan or fast first response should not count as a completed task.

Keep service choices visible

Record reasoning controls, service tiers, token limits and concurrency. GPT-6.1 Sol now offers an Ultrafast Responses mode; a comparison with that mode enabled is a distinct experiment from a standard-tier run.

Three criteria for this comparison

  1. Correct final artifacts after multi-step execution
  2. Tool adapter fidelity and failure recovery
  3. Full completion time and accepted-task cost

Run a fair comparison

Use the same representative inputs and a written answer rubric. Pin the model version and record the endpoint, thinking configuration, quantization when known, context length, output allowance and concurrency. Preserve native request differences in an adapter rather than silently dropping fields.

Measure full request time, error rate and reported usage. For tools, validate arguments and score the result after execution. For images, preserve resolution and preprocessing. A valid response format alone does not establish a correct answer.

Compare cost per accepted result

Calculate input cost plus all billed output, including reasoning where the provider counts it. Add retries and discarded answers. Divide the total by the number of results that pass your quality criteria. Keep API usage cost separate from deployment and engineering cost.

Estimate token costs with the API calculator →

Independent benchmark evidence

Open the full live comparison →
Latest recorded measurements aligned by exact artifact, benchmark version, source and methodology. These are source results, not tests of Flonno's deployment.
Benchmark / sourceGPT-6.1 SolGemini 3.8 Flash
Artificial Analysis Intelligence Indexv4.3 · Artificial Analysis51.8 index_pointsMeasured Sep 30, 2026Original result ↗40.9 index_pointsMeasured Sep 20, 2026Original result ↗

Artificial Analysis observations are refreshed by the integrated Radar. Differences in artifact, benchmark version or method prevent a score comparison. Read the evidence methodology →

YOUR WORKLOAD

Compare cost per accepted task.

Enter results from your own evaluation. A task should count once it meets your written quality criteria. Include failed attempts and retries in total spend. These inputs stay in this browser and are not a Flonno benchmark.

GPT-6.1 Sol
Gemini 3.8 Flash
GPT-6.1 Sol

Enter all four values. Attempted tasks must be at least one; accepted tasks cannot exceed attempted tasks.

Gemini 3.8 Flash

Enter all four values. Attempted tasks must be at least one; accepted tasks cannot exceed attempted tasks.

Turn evidence into a deployment decision

A source benchmark can inform your shortlist, while your evaluation shows whether a model finishes the work at an acceptable cost. Keep the chosen endpoint, processing terms and output limits in the decision record. Inclusion in the Radar does not mean the model is served by Flonno.

For the API currently offered here, explore Qwen3.8 Flash 27B and the production evaluation guide.

Release coverage and updates

Model journal →

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