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Head-to-head comparison

Seed 2.1 Turbo vs GPT-5.6 Terra

Seed 2.1 Turbo (ByteDance Seed) and GPT-5.6 Terra (OpenAI) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 10 September 2026

As of 10 September 2026, Seed 2.1 Turbo holds the stronger ModelCap Index position (#18 vs #19); Seed 2.1 Turbo is 4.8× cheaper per output token ($2.50/1M vs $12.00/1M); and GPT-5.6 Terra offers the longer context window (1M vs 262K tokens).

Which should you choose?

Choose Seed 2.1 Turbo if…

  • you want the stronger overall ModelCap Index position — #18 against #19 (76.8 vs 76.3 points).
  • API cost matters — $2.50/1M output tokens against $12.00/1M, about 4.8× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.50/1M against $2.00/1M.
  • you want the more recently listed model — Seed 2.1 Turbo was listed 12 August 2026, GPT-5.6 Terra 9 July 2026.

Choose GPT-5.6 Terra if…

  • you need the longer context window — 1M tokens against 262K.
  • you want provider choice — 3 listed API providers against 1.

Seed 2.1 Turbo vs GPT-5.6 Terra: specs, pricing and context

Specification comparison of Seed 2.1 Turbo and GPT-5.6 Terra
FieldSeed 2.1 TurboByteDance SeedGPT-5.6 TerraOpenAI
ModelCap Index position#18#19
Index score76.876.3
EvidenceEstimatedMeasured
Input price / 1M tokens$0.50$2.00
Output price / 1M tokens$2.50$12.00
Context window262K tokens1M tokens
Max output tokens236K128K
API providers listed13
Weight accessAPI onlyAPI only
Input modalitiesText, Image, VideoFile, Image, Text
First listed12 August 20269 July 2026
PublisherByteDance SeedOpenAI

Evidence: global-corpus-prior over 185 held-out anchors (12%); launch card against 2 resolved peers on 3 rows (88%); exceeds every named peer on 1 of 3 rows; no cross-lab optimism probe available; shrunk 3.1 toward the measured corpus · 6 public benchmark observations across 6 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Seed 2.1 Turbo vs GPT-5.6 Terra

Public benchmark boards where Seed 2.1 Turbo or GPT-5.6 Terra has a published result
BoardSeed 2.1 TurboGPT-5.6 TerraLeads
Arena codingArena (LMArena)—15191511–1527X-HighOnly one result
LMArena AgentLMArena—1.5%0.3%–2.7%X-HighOnly one result
ARC-AGI-2ARC Prize Foundation—83.9%MaxOnly one result
ARC-AGI-3ARC Prize Foundation—0.8%MaxOnly one result
AA Intelligence IndexArtificial Analysis—42.3intelligence-index:v4.3:maxOnly one result
AA Terminal-Bench 2.1Artificial Analysis—88.0%terminal-bench:2.1:terminus-2:e2b:pass-at-1:3-repeats:source-model="GPT-5.6 Terra (max)":reasoning=trueOnly one result
AA τ²-Bench TelecomArtificial Analysis—86.3%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="GPT-5.6 Terra (max)":reasoning=trueOnly one result
AA Humanity's Last ExamArtificial Analysis—42.9%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-5.6 Terra (max)":reasoning=trueOnly one result
Terminal-Bench 4.0Terminal-Bench (Laude Institute)—21.5%18.3%–24.8%Codex · MaxOnly one result

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Seed 2.1 Turbo vs GPT-5.6 Terra: common questions

Is Seed 2.1 Turbo better than GPT-5.6 Terra?

Seed 2.1 Turbo ranks higher on the ModelCap Index as of 10 September 2026: #18 against #19. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.

Is Seed 2.1 Turbo cheaper than GPT-5.6 Terra?

Seed 2.1 Turbo is cheaper on output tokens: $2.50/1M against $12.00/1M. Input tokens are $0.50/1M for Seed 2.1 Turbo and $2.00/1M for GPT-5.6 Terra. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $2.25 for Seed 2.1 Turbo versus $10.00 for GPT-5.6 Terra. Seed 2.1 Turbo costs 77.5% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.

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

GPT-5.6 Terra has the larger context window: 1M tokens against 262K.

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

The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.

Are Seed 2.1 Turbo and GPT-5.6 Terra open-weight models?

Seed 2.1 Turbo: API only. GPT-5.6 Terra: API only. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run Seed 2.1 Turbo and GPT-5.6 Terra?

ModelCap currently lists 1 API provider for Seed 2.1 Turbo and 3 for GPT-5.6 Terra, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Seed 2.1 Turbo vs GPT-5.6 Terra comparison?

Every figure comes from the sealed ModelCap dataset published 10 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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