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BenchLM
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Model A
GPT-5.6 Terra

OpenAI

71.13/100

Estimated · Public rank #12

90% interval 65.4–76.9

GPT-5.6 Terra vs Seed 2.1 Turbo

Updated September 10, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.

ByteDance logo
Model B
Seed 2.1 Turbo

ByteDance

—

Evidence status unavailable

90% interval unavailable

Decision reading

At least one model is not scored in the current public ranking lane, so the page does not name an overall quality winner.

1 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.

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Which one for your work

Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.

  • Long documents

    Prompts that approach the documented context limit

    GPT-5.6 Terra

    GPT-5.6 Terra has the larger documented context window.

    Confidence: documented

Show secondary and unsupported calls

  • Coding work

    Code generation, repair, and software-engineering tasks

    Not enough matched evidence

    Seed 2.1 Turbo is not ranked on the public lane for coding, so no winner is named for coding.

    Confidence: limited

  • Agentic work

    Tool use, computer use, and multi-step task completion

    Not enough matched evidence

    Seed 2.1 Turbo is not ranked on the public lane for agentic, so no winner is named for agentic.

    Confidence: limited

  • Chat turn cost

    1K fresh input + 500 output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates

  • Cache-heavy agent loop cost

    200K cached + 20K fresh input + 10K output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates

  • Repository review cost

    50K fresh input + 3K output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates

What is actually comparable

Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.

Shared results
1
GPT-5.6 Terra only
30
Seed 2.1 Turbo only
10
Like-for-like categories
0 / 8

Category results, on a stated basis

Each row shows the public-lane category score for both models: the BenchAlign lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.

Agentic

Not comparable
GPT-5.6 Terra
60.2
Supported · #20/152
Seed 2.1 Turbo
Not ranked
Basis
BenchAlign lane · 8 vs 1 public rows
Reading
Not comparable

Coding

Not comparable
GPT-5.6 Terra
67.0
Supported · #8/151
Seed 2.1 Turbo
Not ranked
Basis
BenchAlign lane · 8 vs 2 public rows
Reading
Not comparable

Reasoning

Not comparable
GPT-5.6 Terra
63.7
#14/20
Seed 2.1 Turbo
Not ranked
Basis
Provisional lane · 2 vs 0 weighted rows
Reading
Not comparable

Knowledge

Not comparable
GPT-5.6 Terra
69.2
Supported · #16/183
Seed 2.1 Turbo
Not ranked
Basis
BenchAlign lane · 8 vs 1 public rows
Reading
Not comparable

Math

Not comparable
GPT-5.6 Terra
97.0
Unranked · 3 rankable rows
Seed 2.1 Turbo
Not ranked
Basis
Provisional lane · 2 vs 0 weighted rows
Reading
Not comparable

Multilingual

Not comparable
GPT-5.6 Terra
Not ranked
Seed 2.1 Turbo
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Multimodal

Not comparable
GPT-5.6 Terra
77.1
#15/48
Seed 2.1 Turbo
Not ranked
Basis
Provisional lane · 1 vs 2 weighted rows
Reading
Not comparable

Instruction following

Not comparable
GPT-5.6 Terra
87.1
#34/123
Seed 2.1 Turbo
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign) differ from the provisional-lane categories. Unranked scores sit on the lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.

Shape of the matched evidence

Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.

Too few matched category axes support a radar. The ruled list below shows only shared benchmark results; positions use each benchmark’s normalized display scale when available.

What each workload costs

Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.

Chat turn

1K fresh input + 500 output tokens

GPT-5.6 Terra
$0.01
Fits in one request
Seed 2.1 Turbo
API rate not published
Fits in one request

Seed 2.1 Turbo has no comparable published API token rate.

Repository review

50K fresh input + 3K output tokens

GPT-5.6 Terra
$0.17
Fits in one request
Seed 2.1 Turbo
API rate not published
Fits in one request

Seed 2.1 Turbo has no comparable published API token rate.

Cache-heavy agent loop

200K cached + 20K fresh input + 10K output tokens

GPT-5.6 Terra
$0.25
Fits in one request
Seed 2.1 Turbo
API rate not published
Fits in one request
Cached-input rate unavailable

Seed 2.1 Turbo has no comparable published API token rate.

Specification differences

Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.

Cached-input rate

A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.

GPT-5.6 Terra

$0.25 per 1M cached input tokens

OpenAI API pricing

Seed 2.1 Turbo

No comparable hosted API rate

Volcengine model pricing

Provider availability

GPT-5.6 Terra

Generally Available · OpenAI Responses API

OpenAI model catalog

Seed 2.1 Turbo

Not sourced

Reasoning profile

GPT-5.6 Terra

Reasoning

Seed 2.1 Turbo

Reasoning

Weight access

GPT-5.6 Terra

Proprietary

Seed 2.1 Turbo

Proprietary

License

GPT-5.6 Terra

Proprietary

Seed 2.1 Turbo

Proprietary

Release date

GPT-5.6 Terra

2026-07-09

Seed 2.1 Turbo

2026-06-24

If you already use one of these models
Deployment change
The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
Quality signal
At least one model is not scored in the current public ranking lane, so the page does not name an overall quality winner.
Workload cost
A complete comparable API-rate estimate is not available for both models.
Context tradeoff
GPT-5.6 Terra has the larger documented window (1.05M).

Run the same representative tasks against both endpoints before changing production traffic.

Benchmark evidence

The full public result ledger is available for audit without forcing a wide desktop table onto a phone.

Browse raw public benchmark evidence41 rows

Agentic

  • Terminal-Bench 3.0

    GPT-5.6 Terra20.8%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • Terminal-Bench 2.0

    GPT-5.6 Terra87.4%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • BrowseComp

    GPT-5.6 Terra87.5%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • OSWorld 2.0

    GPT-5.6 Terra50.2%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • CyberGym

    GPT-5.6 Terra81.8%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • ExploitGym

    GPT-5.6 Terra23.2%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • Toolathlon

    GPT-5.6 Terra53.1%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • Terminal-Bench 2.1 (Vals)

    GPT-5.6 Terra77.5%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • Terminal-Bench 2.1

    GPT-5.6 Terra—
    Seed 2.1 Turbo67.6%
    Source

    Not directly comparable

Coding

  • SWE-bench Pro

    GPT-5.6 Terra63.4%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • Terminal-Bench 2.0

    GPT-5.6 Terra87.4%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • DeepSWE

    GPT-5.6 Terra69.6%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • FrontierCode 1.1 Extended

    GPT-5.6 Terra55.8%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • cursorBench32

    GPT-5.6 Terra64.9%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • VulcanBench v3

    GPT-5.6 Terra87.0%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • LiveCodeBench (Vals)

    GPT-5.6 Terra85.9%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • SWE-bench (Vals)

    GPT-5.6 Terra95.4%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • Terminal-Bench 2.1

    GPT-5.6 Terra—
    Seed 2.1 Turbo67.6%
    Source

    Not directly comparable

  • NL2Repo

    GPT-5.6 Terra—
    Seed 2.1 Turbo43.7%
    Source

    Not directly comparable

Reasoning

  • ARC-AGI-2

    GPT-5.6 Terra83.9%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • ARC-AGI-3

    GPT-5.6 Terra0.8%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

Knowledge

  • GPQA

    GPT-5.6 Terra92.9%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • GPQA-D

    GPT-5.6 Terra92.9%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • HLE-Verified

    GPT-5.6 Terra51.1%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • LABBench2

    GPT-5.6 Terra81.2%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • HealthBench Professional

    GPT-5.6 Terra57.7%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • HealthBench Hard

    GPT-5.6 Terra32.7%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • GPQA Diamond (Vals)

    GPT-5.6 Terra90.9%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • MMLU-Pro (Vals)

    GPT-5.6 Terra86.7%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • SuperGPQA

    GPT-5.6 Terra—
    Seed 2.1 Turbo67.4%
    Source

    Not directly comparable

Math

  • FrontierMath (legacy)

    GPT-5.6 Terra84.9%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • FrontierMath v2 (Tiers 1-3)

    GPT-5.6 Terra84.900%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • FrontierMath v2 (Tier 4)

    GPT-5.6 Terra68.300%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

Multimodal

  • MMMU-Pro

    GPT-5.6 Terra80.7%
    Source
    Seed 2.1 Turbo80.1%
    Source

    GPT-5.6 Terra leads this result

  • MMMU-Pro w/ Python

    GPT-5.6 Terra82%
    Source
    Seed 2.1 Turbo—

    Not directly comparable

  • MathVision

    GPT-5.6 Terra—
    Seed 2.1 Turbo90.1%
    Source

    Not directly comparable

  • ZeroBench

    GPT-5.6 Terra—
    Seed 2.1 Turbo11.0%
    Source

    Not directly comparable

  • BabyVision

    GPT-5.6 Terra—
    Seed 2.1 Turbo62.9%
    Source

    Not directly comparable

  • CharXiv

    GPT-5.6 Terra—
    Seed 2.1 Turbo82.5%
    Source

    Not directly comparable

  • ERQA

    GPT-5.6 Terra—
    Seed 2.1 Turbo71.3%
    Source

    Not directly comparable

  • Video-MME

    GPT-5.6 Terra—
    Seed 2.1 Turbo89.0%
    Source

    Not directly comparable

Frequently asked questions

Which is better, GPT-5.6 Terra or Seed 2.1 Turbo?

At least one model is not scored in the current public ranking lane, so the page does not name an overall quality winner. The page therefore keeps the decision tied to the specific documented workload.

Which is better for coding, GPT-5.6 Terra or Seed 2.1 Turbo?

Seed 2.1 Turbo is not ranked on the public lane for coding, so no winner is named for coding.

Which is better for agentic tasks, GPT-5.6 Terra or Seed 2.1 Turbo?

Seed 2.1 Turbo is not ranked on the public lane for agentic tasks, so no winner is named for agentic tasks.

Which costs less, GPT-5.6 Terra or Seed 2.1 Turbo?

Both models do not have comparable published API token rates, so this page does not name a universal price winner.

Which has the larger context window, GPT-5.6 Terra or Seed 2.1 Turbo?

GPT-5.6 Terra has the larger documented context window: 1.05M, compared with 256K.

Related comparisons

Compare API pricing Read the methodology Open the model selector

Last updated September 10, 2026

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