Model comparison

GPT-5.6 Luna vs Hy4 preview

GPT-5.6 Luna is the stronger model overall, scoring 54.6 to 45.3 on the Noometry Index.

Last verified . 3 shared benchmarks.

GPT-5.6 Luna OpenAI

54.6

Rank #30 Confirmed

Hy4 preview Tencent

45.3

Rank #73 Reported

Summary

  • They share 3 benchmarks with published results for both. GPT-5.6 Luna scores higher in 3 categories and Hy4 preview in 0 categories; 3 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.6 Luna leads 77.7 to 55.7.
  • The biggest single-benchmark swing is ProofBench: 60% for GPT-5.6 Luna and 75% for Hy4 preview.
  • GPT-5.6 Luna is cheaper at $0.20 / $1.20 per million input/output tokens, against $0.75 / $2.25 for Hy4 preview.
  • GPT-5.6 Luna accepts more context: 1.05M tokens versus 1.05M.
  • Hy4 preview has downloadable open weights; the other is API-only.

Side by side

GPT-5.6 Luna and Hy4 preview specifications
GPT-5.6 LunaHy4 preview
ProviderOpenAITencent
Noometry Index54.645.3
Released2026-07-092026-08-28
WeightsProprietaryOpen
Context window1.05M1.05M
Max output128K64K
Input $ / M tokens$0.20$0.75
Output $ / M tokens$1.20$2.25
Results tracked523

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Category by category

Coding GPT-5.6 Luna leads

GPT-5.6 Luna: 54.5 (#28), Hy4 preview: 51.6 (#38)

Coding benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
LMArena WebDev15191632
DeepSWE67.2%—
FrontierCode39.8%—
CursorBench35.9%—
SciCode53.6%—
WeirdML60.9%—
LMArena Coding1466—
ALE-Bench1,667—

Agentic & Tool Use Not comparable

GPT-5.6 Luna: 34.4 (#45), Hy4 preview: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
APEX-Agents43%—
BALROG45.6%—
GDP.pdf22.7%—
Vending-Bench 24,095—

Reasoning GPT-5.6 Luna leads

GPT-5.6 Luna: 47.6 (#43), Hy4 preview: 31.9 (#79)

Reasoning benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
NYT Connections (extended)69.4%68.2%
ARC-AGI-259.5%—
SimpleBench46.8%—
Kagi LLM Benchmark49.1%—
ARC-AGI-188%—
CritPt20.6%—
Chess Puzzles40%—
LMArena Hard Prompts1451—
Mystery Game Puzzles21%—
DTBench89.1%—
LMCA48.5%—
Surface Evolver Bench61.9%—
Epoch Capabilities Index156.39—

Math GPT-5.6 Luna leads

GPT-5.6 Luna: 77.7 (#14), Hy4 preview: 55.7 (#42)

Math benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
ProofBench60%75%
FrontierMath (Tiers 1-3)82.1%—
FrontierMath Tier 461%—
OTIS Mock AIME 2024-202598.3%—
LMArena Math1458—

Knowledge Not comparable

GPT-5.6 Luna: 58.5 (#34), Hy4 preview: —

Knowledge benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
GPQA Diamond91.6%—
SimpleQA Verified41%—
LMArena Expert1478—

Multimodal Not comparable

GPT-5.6 Luna: 42.7 (#28), Hy4 preview: —

Multimodal benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
LMArena Vision1258—
Blueprint-Bench 222.6%—
Furniture Assembly42.5%—
LMArena Document1457—

Multilingual Not comparable

GPT-5.6 Luna: 52.8 (#78), Hy4 preview: —

Multilingual benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
LMArena Non-English1417—
LMArena Chinese1470—
LMArena French1456—
LMArena German1454—
LMArena Japanese1411—
LMArena Korean1415—
LMArena Russian1428—
LMArena Spanish1448—

Instruction Following Not comparable

GPT-5.6 Luna: 75.6 (#57), Hy4 preview: —

Instruction Following benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
LMArena Instruction Following1437—

Long Context Not comparable

GPT-5.6 Luna: 43.9 (#82), Hy4 preview: —

Long Context benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
LMArena Longer Query1436—

Writing & Preference Not comparable

GPT-5.6 Luna: 68.0 (#29), Hy4 preview: —

Writing & Preference benchmarks
BenchmarkGPT-5.6 LunaHy4 preview
LMArena Text1431—
LMArena Creative Writing1396—
EQ-Bench Creative Writing1829—
EQ-Bench 41156—
LMArena Multi-Turn1434—

Frequently asked questions

Is GPT-5.6 Luna better than Hy4 preview?

GPT-5.6 Luna is the stronger model overall, scoring 54.6 to 45.3 on the Noometry Index.

Which is cheaper, GPT-5.6 Luna or Hy4 preview?

GPT-5.6 Luna is cheaper. It lists at $0.20 per million input tokens and $1.20 per million output tokens; Hy4 preview lists at $0.75 and $2.25.

Is GPT-5.6 Luna or Hy4 preview better for coding?

GPT-5.6 Luna scores higher on coding benchmarks: 54.5 versus 51.6 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Luna does, with 1.05M tokens against 1.05M.

How many benchmarks do GPT-5.6 Luna and Hy4 preview share?

3 benchmarks have published results for both models. GPT-5.6 Luna has 52 scored results on Noometry and Hy4 preview has 3.

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