Noometry

Model comparison

Grok 4.3 vs Step 5 Preview

Step 5 Preview is the stronger model overall, scoring 47.9 to 43.8 on the Noometry Index.

Last verified . 18 shared benchmarks.

Grok 4.3 xAI

43.8

Rank #86 Confirmed

Step 5 Preview StepFun

47.9

Rank #58 Confirmed

Summary

  • They share 18 benchmarks with published results for both. Grok 4.3 scores higher in 1 category and Step 5 Preview in 8 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Grok 4.3 leads 52.5 to 41.2.
  • The biggest single-benchmark swing is ProofBench: 11% for Grok 4.3 and 42% for Step 5 Preview.
  • Step 5 Preview is cheaper at $1 / $2.70 per million input/output tokens, against $1.25 / $2.50 for Grok 4.3.
  • Step 5 Preview accepts more context: 1.02M tokens versus 1M.

Side by side

Grok 4.3Step 5 Preview
ProviderxAIStepFun
Noometry Index43.847.9
Released2026-04-172026-09-16
WeightsProprietaryProprietary
Context window1M1.02M
Max output30K66K
Input $ / M tokens$1.25$1
Output $ / M tokens$2.50$2.70
Results tracked4018

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Category by category

Coding Step 5 Preview leads

Grok 4.3: 41.6 (#121), Step 5 Preview: 51.8 (#36)

BenchmarkGrok 4.3Step 5 Preview
LMArena WebDev13571564
SciCode47.3%58.9%
LMArena Coding14151480
WeirdML49.9%—
ALE-Bench944.17—

Agentic & Tool Use Not comparable

Grok 4.3: 27.7 (#99), Step 5 Preview: —

BenchmarkGrok 4.3Step 5 Preview
GDP.pdf8%—
LMArena Search1165—
Vending-Bench 235.26—

Reasoning Step 5 Preview leads

Grok 4.3: 35.9 (#68), Step 5 Preview: 40.0 (#57)

BenchmarkGrok 4.3Step 5 Preview
CritPt8%20.9%
LMArena Hard Prompts13961465
NYT Connections (extended)55.2%—
Chess Puzzles25%—
DTBench90.7%—
LMCA38.3%—
Epoch Capabilities Index149.16—
ForecastBench60.3—

Math Too close to call

Grok 4.3: 46.0 (#74), Step 5 Preview: 46.1 (#72)

BenchmarkGrok 4.3Step 5 Preview
ProofBench11%42%
LMArena Math13881470
FrontierMath (Tiers 1-3)42.8%—
FrontierMath Tier 414.6%—
OTIS Mock AIME 2024-202593.3%—

Knowledge Grok 4.3 leads

Grok 4.3: 52.5 (#62), Step 5 Preview: 41.2 (#112)

BenchmarkGrok 4.3Step 5 Preview
LMArena Expert13851470
GPQA Diamond88.8%—
SimpleQA Verified33.2%—

Multimodal Step 5 Preview leads

Grok 4.3: 31.6 (#104), Step 5 Preview: 41.0 (#41)

BenchmarkGrok 4.3Step 5 Preview
LMArena Vision12291267
Blueprint-Bench 20%—

Multilingual Step 5 Preview leads

Grok 4.3: 50.5 (#120), Step 5 Preview: 53.8 (#54)

BenchmarkGrok 4.3Step 5 Preview
LMArena Non-English13851432
LMArena Chinese14221519
LMArena Russian13991436
LMArena Spanish13981439
LMArena French1412—
LMArena German1395—
LMArena Japanese1379—
LMArena Korean1356—

Instruction Following Step 5 Preview leads

Grok 4.3: 72.1 (#140), Step 5 Preview: 76.0 (#50)

BenchmarkGrok 4.3Step 5 Preview
LMArena Instruction Following13661444

Long Context Step 5 Preview leads

Grok 4.3: 42.5 (#123), Step 5 Preview: 44.5 (#64)

BenchmarkGrok 4.3Step 5 Preview
LMArena Longer Query13931455

Writing & Preference Step 5 Preview leads

Grok 4.3: 58.5 (#118), Step 5 Preview: 62.8 (#71)

BenchmarkGrok 4.3Step 5 Preview
LMArena Text13971442
LMArena Creative Writing13801410
LMArena Multi-Turn14061447
EQ-Bench 41075—

Frequently asked questions

Is Grok 4.3 better than Step 5 Preview?

Step 5 Preview is the stronger model overall, scoring 47.9 to 43.8 on the Noometry Index.

Which is cheaper, Grok 4.3 or Step 5 Preview?

Step 5 Preview is cheaper. It lists at $1 per million input tokens and $2.70 per million output tokens; Grok 4.3 lists at $1.25 and $2.50.

Is Grok 4.3 or Step 5 Preview better for coding?

Step 5 Preview scores higher on coding benchmarks: 51.8 versus 41.6 in the Noometry coding category.

Which has the bigger context window?

Step 5 Preview does, with 1.02M tokens against 1M.

How many benchmarks do Grok 4.3 and Step 5 Preview share?

18 benchmarks have published results for both models. Grok 4.3 has 40 scored results on Noometry and Step 5 Preview has 18.

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