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Model comparison

DeepSeek V4 Flash vs GPT-5.6 Terra

DeepSeek against OpenAI, compared on context, price, and verified benchmark results.

Catalog record checked September 3, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

DeepSeek

DeepSeek V4 Flash

Balanced · Open weights

vs

OpenAI

GPT-5.6 Terra

Balanced

AI model capability comparison
SpecificationDeepSeek V4 FlashGPT-5.6 Terra
ProviderDeepSeekOpenAI
TierBalancedBalanced
Context window1MWinner: 1.05M
Max outputWinner: 384K128K
Input / 1M tokensWinner: $0.44$2
Output / 1M tokensWinner: $1.32$12
WeightsOpenClosed
Parameters284B total / 13B active (MoE)mid-tier reasoning model
Reasoning levelslow, high, maxnone, low, medium, high, xhigh, max
Modalitiestexttext, image
LicenseMITNot disclosedUnverified
API model iddeepseek-v4-flashgpt-5.6-terra
ReleasedApril 24, 2026July 9, 2026
Artificial Analysis Intelligence Index (2026-08-14)49Not verifiedUnverified
Artificial Analysis Intelligence Index [high] (2026-08-14)Not verifiedUnverified50
SWE-bench Verified (2026-04-24)79Winner: 95.4
GPQA Diamond (2026-04-24)88.1Not verifiedUnverified
Humanity's Last Exam (2026-04-24)45.1Not verifiedUnverified
MMLU-Pro (2026-04-24)86.2Not verifiedUnverified
Terminal-Bench 2.1 (2026-07-09)Not verifiedUnverified87.4
LiveBench (2026-09-05)Not verifiedUnverified77.9

Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

  • 2026-09-05: LiveBench official leaderboard (benchmark-owned), max effortContamination-resistant general capability across reasoning, coding, math, data analysis, and language, with monthly question refreshes. Comparability: comparable with caveat — Rolling question set: observations months apart measure different question mixes. Record the measurement date and compare within ~1 month windows.
  • 2026-09-01: vals.ai SWE-bench Verified leaderboard (independent, mini-swe-agent bash-only) (independent; official SWE-bench not published)Real GitHub issue resolution: does the model's patch pass the hidden tests. Comparability: comparable with caveat — Post-audit vendor claims and pre-audit scores sit on different task trust levels; scaffolding (agent harness, compute budget) also dominates results. Never aggregate across scaffolds.
  • 2026-08-14: Artificial AnalysisComposite index blending reasoning, knowledge, and coding evals into one 0–100 score. Comparability: directly comparable — AA occasionally rebaselines the index scale between snapshots — a score captured on one date is only comparable to same-snapshot scores (check measuredAt).
  • 2026-07-09: OpenAI GPT-5.6 announcement (vendor; chart transcribed by Vellum)Agentic terminal work: multi-step tasks executed in a sandboxed shell environment. Comparability: comparable with caveat — Scores across Terminal-Bench major versions (v1 vs v2) are NOT comparable; harness configuration (container, time limits) also shifts results.
  • 2026-04-24: DeepSeek family HF model card (vendor, Think Max, exact match)Real GitHub issue resolution: does the model's patch pass the hidden tests. Comparability: comparable with caveat — Post-audit vendor claims and pre-audit scores sit on different task trust levels; scaffolding (agent harness, compute budget) also dominates results. Never aggregate across scaffolds.

Pricing tiers: DeepSeek V4 Flash: Official peak rates $0.44/$1.32 per MTok; off-peak $0.22/$0.66 (cache hit $0.014). Open weights (MIT). 284B/13B active MoE. · GPT-5.6 Terra: Launch list was $2.50/$15; cut to $2/$12 on 2026-07-30. Cached input $0.20/MTok; batch $1/$6.

BalancedOpen weightsRecord checked September 3, 2026

DeepSeek V4 Flash

DeepSeek V4 Flash is the efficient open-weight (MIT) sibling of V4 Pro with a 1M-token context.

Best for

  • Open-weight deployments
  • Cost-sensitive inference
  • High-volume serving

Watch out

Peak/off-peak billing means the hour you run matters; off-peak is half price.

BalancedRecord checked September 3, 2026

GPT-5.6 Terra

GPT-5.6 Terra delivers roughly GPT-5.5-class quality at about half the cost, with the full 1.05M-token context.

Best for

  • Cost-sensitive production
  • Mixed reasoning workloads
  • High-volume agents

Watch out

Quality trails Sol on the hardest tasks; route frontier work to Sol when it matters.

When the cheaper one wins

DeepSeek V4 Flash is cheaper on output at $1.32 per million tokens against $12 for GPT-5.6 Terra — about 9.1×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.

Run the model picker

Evidence confidence: High

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 5/5 core specs verified on both sides — All core specifications verified for both models.
  • 2 shared named benchmarks with differing scores — Measured on: Artificial Analysis Intelligence Index, SWE-bench Verified.
  • Verified within the last 90 days — Newest catalog check was 8 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? DeepSeek V4 Flash · GPT-5.6 Terra

Common questions

DeepSeek V4 Flash vs GPT-5.6 Terra

Answered from the verified figures on this page rather than general guidance.

Is DeepSeek V4 Flash or GPT-5.6 Terra cheaper for input?

DeepSeek V4 Flash is cheaper at $0.44 per million input tokens, against $2 for GPT-5.6 Terra — roughly 4.5× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; DeepSeek V4 Flash has tiered pricing: Official peak rates $0.44/$1.32 per MTok; off-peak $0.22/$0.66 (cache hit $0.014). Open weights (MIT). 284B/13B active MoE. GPT-5.6 Terra has tiered pricing: Launch list was $2.50/$15; cut to $2/$12 on 2026-07-30. Cached input $0.20/MTok; batch $1/$6.

Is DeepSeek V4 Flash or GPT-5.6 Terra cheaper for output?

DeepSeek V4 Flash is cheaper at $1.32 per million output tokens, against $12 for GPT-5.6 Terra — roughly 9.1× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; DeepSeek V4 Flash has tiered pricing: Official peak rates $0.44/$1.32 per MTok; off-peak $0.22/$0.66 (cache hit $0.014). Open weights (MIT). 284B/13B active MoE. GPT-5.6 Terra has tiered pricing: Launch list was $2.50/$15; cut to $2/$12 on 2026-07-30. Cached input $0.20/MTok; batch $1/$6.

Which has the larger context window, DeepSeek V4 Flash or GPT-5.6 Terra?

GPT-5.6 Terra accepts 1.05M tokens against 1M for DeepSeek V4 Flash. This only matters if you routinely send very long documents or large codebases.

Do DeepSeek V4 Flash and GPT-5.6 Terra support the same reasoning levels?

DeepSeek V4 Flash exposes low, high, max, while GPT-5.6 Terra exposes none, low, medium, high, xhigh, max.

Should I use DeepSeek V4 Flash or GPT-5.6 Terra?

Both sit in the balanced tier, so the choice usually comes down to price and context rather than capability. DeepSeek V4 Flash suits open-weight deployments; GPT-5.6 Terra suits cost-sensitive production.

Can I self-host DeepSeek V4 Flash or GPT-5.6 Terra?

DeepSeek V4 Flash publishes open weights, but self-hosting and third-party provider access depend on the licence, hardware, serving support, and availability. GPT-5.6 Terra is a closed model whose supported access paths are controlled by its provider.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Input price: DeepSeek V4 Flash costs $0.44 per 1M tokens versus $2 for GPT-5.6 Terra — a 4.5x difference at the headline tier.
  • Context: GPT-5.6 Terra takes 1.05M against 1M for DeepSeek V4 Flash — only decisive if your prompts approach the smaller window.
  • Measured capability: GPT-5.6 Terra leads Artificial Analysis Intelligence Index 50 to 49 (measured 2026-08-14).
  • Deployment: DeepSeek V4 Flash publishes weights you can self-host; the other is API-only.
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