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GPT-5.1-Codex vs Hy3

Updated October 21, 2026. 11 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace GPT-5.1-Codex Replace Hy3
GPT-5.1-CodexOpenAI
Coding
50.5
Overall
23.7
Output $/M
$10.00
3
Hy3Tencent
Coding
43.9
Overall
No data
Output $/M
$0.528
8
vs boards won of 11 shared

Decision reading

Pick GPT-5.1-Codex for coding: it scores 50.5 on the Vibe Coding Index against 43.9 for Hy3.

Pick Hy3 when output tokens cost 18.9x less, or when what matters is LMArena WebDev or LMArena WebDev: HTML, where it leads.

Model AGPT-5.1-CodexOpenAI50.5/1002 independent benchmarks$0.892 per solved taskModel BHy3Tencent43.9/1001 independent benchmarkNo cost per solved task
Shared results
11
GPT-5.1-Codex only
15
Hy3 only
33
Like-for-like categories
4 of 9

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

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
GPT-5.1-Codex 50.5 from 2 benchmarks, Hy3 43.9 from 1 benchmark.
Widest category
Coding, 20.4 points apart on average over 3 shared benchmarks.
Widest single gap
LMArena WebDev: GPT-5.1-Codex 1337 against Hy3 1507, 24.3 points apart on a 0 to 100 scale.
Output price
GPT-5.1-Codex $10.00 against Hy3 $0.528 per million output tokens, 18.9x apart.
Context window
GPT-5.1-Codex takes 400K tokens, Hy3 262K.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryGPT-5.1-CodexBarsHy3Ties
Coding12
Reasoning02
Web design23
General01
All shared boards38
CodingLike-for-likeFour of these boards feed the Vibe Coding Index12
Coding benchmarks for GPT-5.1-Codex and Hy3
BenchmarkGPT-5.1-CodexHy3Leader
SWE-bench Verified66.0%Not measuredOnly GPT-5.1-Codex measured
LMArena WebDev13371507Hy3
LiveCodeBench (Vals AI)85.5%Not measuredOnly GPT-5.1-Codex measured
Vibe Code Bench (Vals AI)13.1%Not measuredOnly GPT-5.1-Codex measured
LiveCodeBench (Artificial Analysis run)84.9%Not measuredOnly GPT-5.1-Codex measured
SciCodeNot measured48.6%Only Hy3 measured
Terminal-Bench Hard (Artificial Analysis run)34.8%Not measuredOnly GPT-5.1-Codex measured
Terminal-Bench57.8%Not measuredOnly GPT-5.1-Codex measured
ALE-Bench1244.9838.6GPT-5.1-Codex
LMArena Text: codingNot measured1466Only Hy3 measured
LMArena Text: software and ITNot measured1463Only Hy3 measured
LMArena WebDev: ReactNot measured1511Only Hy3 measured
LMArena WebDev: HTML13461487Hy3
Neither model has a result on the other 25 boards here
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
Intelligence benchmarks for GPT-5.1-Codex and Hy3
BenchmarkGPT-5.1-CodexHy3Leader
AA Intelligence Index23.7Not measuredOnly GPT-5.1-Codex measured
Neither model has a result on the other 1 board here
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
Agentic work benchmarks for GPT-5.1-Codex and Hy3
BenchmarkGPT-5.1-CodexHy3Leader
Design Arena: agents building web apps1018Not measuredOnly GPT-5.1-Codex measured
Design Arena: agents building full-stack apps1086Not measuredOnly GPT-5.1-Codex measured
Design Arena: agents building mobile apps1191Not measuredOnly GPT-5.1-Codex measured
τ²-Bench Telecom83.0%Not measuredOnly GPT-5.1-Codex measured
Neither model has a result on the other 35 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index02
Reasoning benchmarks for GPT-5.1-Codex and Hy3
BenchmarkGPT-5.1-CodexHy3Leader
GPQA Diamond (Artificial Analysis run)86.0%89.7%Hy3
Humanity's Last Exam (Artificial Analysis run)25.7%33.5%Hy3
LMArena Text: hard promptsNot measured1447Only Hy3 measured
LMArena Text: expertNot measured1461Only Hy3 measured
LMArena Text: hard prompts in EnglishNot measured1455Only Hy3 measured
Neither model has a result on the other 16 boards here
MathDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
Math benchmarks for GPT-5.1-Codex and Hy3
BenchmarkGPT-5.1-CodexHy3Leader
AA Math Index95.7Not measuredOnly GPT-5.1-Codex measured
AIME 2025 (Artificial Analysis run)95.7%Not measuredOnly GPT-5.1-Codex measured
LMArena Text: mathNot measured1473Only Hy3 measured
LMArena Text: mathematical workNot measured1482Only Hy3 measured
Neither model has a result on the other 9 boards here
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index5 boards, none shared
Knowledge benchmarks for GPT-5.1-Codex and Hy3
BenchmarkGPT-5.1-CodexHy3Leader
MMLU Pro (Artificial Analysis run)86.0%Not measuredOnly GPT-5.1-Codex measured
LMArena Text: scienceNot measured1457Only Hy3 measured
LMArena Text: medicine and healthcareNot measured1452Only Hy3 measured
LMArena Text: legal and governmentNot measured1422Only Hy3 measured
LMArena Text: business and financeNot measured1424Only Hy3 measured
Neither model has a result on the other 12 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index23
Web design benchmarks for GPT-5.1-Codex and Hy3
BenchmarkGPT-5.1-CodexHy3Leader
Design Arena: websites11621230Hy3
Design Arena: UI components12371205GPT-5.1-Codex
Design Arena: game dev11381208Hy3
Design Arena: data viz12131163GPT-5.1-Codex
Design Arena: 3DNot measured1233Only Hy3 measured
Design Arena: all code categories11531227Hy3
Design Arena: SVGNot measured1199Only Hy3 measured
Design Arena: ASCII artNot measured1157Only Hy3 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index01
General benchmarks for GPT-5.1-Codex and Hy3
BenchmarkGPT-5.1-CodexHy3Leader
IFBench70.0%Not measuredOnly GPT-5.1-Codex measured
Long context reasoning (AA-LCR)69.3%79.0%Hy3
LMArena TextNot measured1438Only Hy3 measured
LMArena Text: instruction followingNot measured1426Only Hy3 measured
LMArena Text: creative writingNot measured1403Only Hy3 measured
LMArena Text: EnglishNot measured1448Only Hy3 measured
LMArena Text: non-EnglishNot measured1426Only Hy3 measured
LMArena Text: ChineseNot measured1485Only Hy3 measured
LMArena Text: GermanNot measured1449Only Hy3 measured
LMArena Text: JapaneseNot measured1397Only Hy3 measured
LMArena Text: KoreanNot measured1396Only Hy3 measured
LMArena Text: FrenchNot measured1456Only Hy3 measured
LMArena Text: SpanishNot measured1457Only Hy3 measured
LMArena Text: RussianNot measured1432Only Hy3 measured
LMArena Text: PolishNot measured1447Only Hy3 measured
LMArena Text: multi-turnNot measured1436Only Hy3 measured
LMArena Text: longer queriesNot measured1442Only Hy3 measured
LMArena Text: writing and languageNot measured1414Only Hy3 measured
LMArena Text: entertainment and mediaNot measured1400Only Hy3 measured
Neither model has a result on the other 27 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for GPT-5.1-Codex and Hy3
BenchmarkGPT-5.1-CodexHy3Leader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

GPT-5.1-Codex$0.0063Fits in one request
Hy3$0.0004Fits in one request

Hy3 costs less

Repository review

50K input + 3K output tokens

GPT-5.1-Codex$0.092Fits in one request
Hy3$0.0082Fits in one request

Hy3 costs less

Agent loop

200K input + 10K output tokens

GPT-5.1-Codex$0.350Fits in one request
Hy3$0.032Fits in one request

Hy3 costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of GPT-5.1-Codex and Hy3
SpecificationOpenAI GPT-5.1-CodexTencent Hy3
MakerOpenAITencent
WeightsNo public weights listedOpen weights
ReleasedNovember 13, 2025July 6, 2026
Context window400K262K
Input $/Mtok$1.25$0.132
Output $/Mtok$10.00$0.528
Coding index50.543.9
Independent measurements behind it21
Cost per solved task$0.892Not computable
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.1-Codex better than Hy3 for coding?

Pick GPT-5.1-Codex for coding: it scores 50.5 on the Vibe Coding Index against 43.9 for Hy3. Pick Hy3 when output tokens cost 18.9x less, or when what matters is LMArena WebDev or LMArena WebDev: HTML, where it leads.

Which is cheaper, GPT-5.1-Codex or Hy3?

GPT-5.1-Codex costs $1.25 per million input tokens and $10.00 per million output tokens; Hy3 costs $0.132 and $0.528. Cost per solved task is known for GPT-5.1-Codex only.

Which has the bigger context window, GPT-5.1-Codex or Hy3?

GPT-5.1-Codex, with 400K tokens against 262K.

How many benchmarks is the GPT-5.1-Codex vs Hy3 comparison based on?

11 benchmarks have a result for both models as of October 21, 2026. GPT-5.1-Codex's coding index rests on 2 independent benchmarks and Hy3's on 1. Where only one model has a result, the page says so instead of naming a winner.

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