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Model comparison

DeepSeek V4.1 Flash vs GPT-6 Sol

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

Catalog record checked September 26, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

DeepSeek

DeepSeek V4.1 Flash

Balanced · Open weights

vs

OpenAI

GPT-6 Sol

Balanced

AI model capability comparison
SpecificationDeepSeek V4.1 FlashGPT-6 Sol
ProviderDeepSeekOpenAI
TierBalancedBalanced
Context window1MWinner: 1.05M
Max outputWinner: 384K128K
Input / 1M tokensWinner: $0.30$2
Output / 1M tokensWinner: $1.20$10
WeightsOpenClosed
Parameters552B MoE (causal encoder-decoder; 8B active for input, 16B for output)GPT-6 mid-price tier
Reasoning levelslow, high, maxnone, low, medium, high, xhigh, max
Modalitiestext, imagetext, image
LicenseMITNot disclosedUnverified
API model iddeepseek-flashgpt-6-sol
ReleasedSeptember 10, 2026September 22, 2026
Artificial Analysis Intelligence Index [max] (2026-09-26)39.5Winner: 47.5
DeepSWE 1.1 [max] (2026-09-10)Winner: 74.268.8
Terminal-Bench 2.1 [max] (2026-09-10)90.6Not verifiedUnverified
GPQA Diamond [max] (2026-09-10)90.9Not verifiedUnverified
OSWorld 2.0 (offline) [xhigh] (2026-09-22)Not verifiedUnverified60.5
Terminal-Bench 4.0 [max] (2026-09-26)Not verifiedUnverified43.9

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

Where each score comes from, and how far it can be compared across models.

  • 2026-09-26
    Artificial Analysis Terminal-Bench 4.0 (independent AA run, part of Intelligence Index v4.3.2)

    Agentic terminal work: long multi-step tasks executed in a sandboxed shell environment.

    Comparable with caveatNOT comparable with Terminal-Bench 2.x or 3.0 — 4.0 uses a new, non-overlapping task set. Within 4.0, scores from different harnesses (tbench.ai agent entries vs Artificial Analysis runs) are not interchangeable.

  • 2026-09-26
    Artificial Analysis

    Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.

    Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check measuredAt.

  • 2026-09-22
    OpenAI — Introducing GPT-6 Sol and Luna (vendor)

    Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task.

    Directly comparable

  • 2026-09-10
    DeepSeek V4.1-Flash release notes (vendor)

    Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task.

    Directly comparable

Pricing tiers

DeepSeek V4.1 Flash: Official peak rates $0.30/$1.20 per MTok; off-peak $0.15/$0.60 (50% of peak). Cache hit $0.006 peak / $0.003 off-peak. Peak hours are weekdays 01:00–04:00 and 06:00–10:00 UTC. Open weights (MIT). The legacy deepseek-v4-flash and deepseek-v4-flash-vision-exp ids temporarily route here.

GPT-6 Sol: Replaces GPT-5.6 Sol at 50% of its $4/$20 promo price. Cached input $0.20/MTok; cache writes $2.50 (1.25x). Above 272K input the whole request bills $4/$15 ($0.40 cached). Batch/Flex $1/$5; Fast mode $4/$20. Knowledge cutoff Apr 20 2026. Launched in the API, ChatGPT Work and Codex the same day.

BalancedOpen weightsRecord checked September 26, 2026

DeepSeek V4.1 Flash

DeepSeek V4.1 Flash is DeepSeek's new default — an open-weight (MIT) multimodal MoE that DeepSeek says beats V4-Pro on performance, cost and speed.

Best for

  • Open-weight price-performance
  • High-volume hosted agents
  • Self-hosting with MIT weights

Watch out

Vendor benchmark claims are far ahead of its independent Artificial Analysis score (39.5 on v4.3.2); peak/off-peak billing means the hour you run matters.

BalancedRecord checked September 26, 2026

GPT-6 Sol

GPT-6 Sol brings GPT-6 Astra's training advances to OpenAI's mid-priced tier — OpenAI claims roughly half GPT-5.6 Sol's factual-error rate at half its price, with a 1.05M-token context.

Best for

  • Default OpenAI production model
  • Agentic coding
  • Long-context knowledge work

Watch out

Brand-new (2026-09-22): the DeepSWE figure is vendor-reported and it is not yet on the independent boards; long prompts above 272K bill $4/$15 for the whole request.

When the cheaper one wins

DeepSeek V4.1 Flash is cheaper on output at $1.20 per million tokens against $10 for GPT-6 Sol — about 8.3×. 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, DeepSWE 1.1.
  • Verified within the last 90 days — Newest catalog check was 2 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 V4.1 Flash · GPT-6 Sol

Common questions

DeepSeek V4.1 Flash vs GPT-6 Sol

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

Is DeepSeek V4.1 Flash or GPT-6 Sol cheaper for input?
DeepSeek V4.1 Flash is cheaper at $0.30 per million input tokens, against $2 for GPT-6 Sol — roughly 6.7× 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 V4.1 Flash has tiered pricing: Official peak rates $0.30/$1.20 per MTok; off-peak $0.15/$0.60 (50% of peak). Cache hit $0.006 peak / $0.003 off-peak. Peak hours are weekdays 01:00–04:00 and 06:00–10:00 UTC. Open weights (MIT). The legacy deepseek-v4-flash and deepseek-v4-flash-vision-exp ids temporarily route here. GPT-6 Sol has tiered pricing: Replaces GPT-5.6 Sol at 50% of its $4/$20 promo price. Cached input $0.20/MTok; cache writes $2.50 (1.25x). Above 272K input the whole request bills $4/$15 ($0.40 cached). Batch/Flex $1/$5; Fast mode $4/$20. Knowledge cutoff Apr 20 2026. Launched in the API, ChatGPT Work and Codex the same day.
Is DeepSeek V4.1 Flash or GPT-6 Sol cheaper for output?
DeepSeek V4.1 Flash is cheaper at $1.20 per million output tokens, against $10 for GPT-6 Sol — roughly 8.3× 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 V4.1 Flash has tiered pricing: Official peak rates $0.30/$1.20 per MTok; off-peak $0.15/$0.60 (50% of peak). Cache hit $0.006 peak / $0.003 off-peak. Peak hours are weekdays 01:00–04:00 and 06:00–10:00 UTC. Open weights (MIT). The legacy deepseek-v4-flash and deepseek-v4-flash-vision-exp ids temporarily route here. GPT-6 Sol has tiered pricing: Replaces GPT-5.6 Sol at 50% of its $4/$20 promo price. Cached input $0.20/MTok; cache writes $2.50 (1.25x). Above 272K input the whole request bills $4/$15 ($0.40 cached). Batch/Flex $1/$5; Fast mode $4/$20. Knowledge cutoff Apr 20 2026. Launched in the API, ChatGPT Work and Codex the same day.
Which has the larger context window, DeepSeek V4.1 Flash or GPT-6 Sol?
GPT-6 Sol accepts 1.05M tokens against 1M for DeepSeek V4.1 Flash. This only matters if you routinely send very long documents or large codebases.
Do DeepSeek V4.1 Flash and GPT-6 Sol support the same reasoning levels?
DeepSeek V4.1 Flash exposes low, high, max, while GPT-6 Sol exposes none, low, medium, high, xhigh, max.
Should I use DeepSeek V4.1 Flash or GPT-6 Sol?
Both sit in the balanced tier, so the choice usually comes down to price and context rather than capability. DeepSeek V4.1 Flash suits open-weight price-performance; GPT-6 Sol suits default openai production model.
Can I self-host DeepSeek V4.1 Flash or GPT-6 Sol?
DeepSeek V4.1 Flash publishes open weights, but self-hosting and third-party provider access depend on the licence, hardware, serving support, and availability. GPT-6 Sol 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 V4.1 Flash costs $0.30 per 1M tokens versus $2 for GPT-6 Sol — a 6.7x difference at the headline tier.
  • Context: GPT-6 Sol takes 1.05M against 1M for DeepSeek V4.1 Flash — only decisive if your prompts approach the smaller window.
  • Measured capability: GPT-6 Sol leads Artificial Analysis Intelligence Index 47.5 to 39.5 (measured 2026-09-26).
  • Deployment: DeepSeek V4.1 Flash publishes weights you can self-host; the other is API-only.
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