Noometry

Model comparison

Grok 4.1 Fast vs Solar Pro4

Grok 4.1 Fast and Solar Pro4 score almost the same on the Noometry Index (41.4 vs 42.1), so choose on price, context window or the category you care about most.

Last verified . 18 shared benchmarks.

Grok 4.1 Fast xAI

41.4

Rank #136 Confirmed

Solar Pro4 Upstage

42.1

Rank #121 Confirmed

Summary

  • They share 18 benchmarks with published results for both. Grok 4.1 Fast scores higher in 4 categories and Solar Pro4 in 4 categories; 5 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Grok 4.1 Fast leads 43.4 to 28.5.
  • Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $0.30 / $1.20 for Solar Pro4.
  • Solar Pro4 accepts more context: 524K tokens versus 128K.

Side by side

Grok 4.1 FastSolar Pro4
ProviderxAIUpstage
Noometry Index41.442.1
Released2025-06-272026-08-06
WeightsProprietaryProprietary
Context window128K524K
Max output30K131K
Input $ / M tokens$0.20$0.30
Output $ / M tokens$0.50$1.20
Results tracked3218

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Category by category

Coding Solar Pro4 leads

Grok 4.1 Fast: 34.1 (#245), Solar Pro4: 40.1 (#149)

BenchmarkGrok 4.1 FastSolar Pro4
LMArena WebDev12421371
LMArena Coding14111437
ALE-Bench394.93—

Agentic & Tool Use Not comparable

Grok 4.1 Fast: 36.3 (#39), Solar Pro4: —

BenchmarkGrok 4.1 FastSolar Pro4
Berkeley Function Calling Leaderboard69.6%—
τ²-bench Banking13.1%—
LMArena Search1171—
Vending-Bench 21,107—

Reasoning Grok 4.1 Fast leads

Grok 4.1 Fast: 43.4 (#49), Solar Pro4: 28.5 (#104)

BenchmarkGrok 4.1 FastSolar Pro4
LMArena Hard Prompts14071399
SimpleBench56%—
NYT Connections (extended)87.4%—
DTBench87.7%—
ForecastBench61—

Math Solar Pro4 leads

Grok 4.1 Fast: 31.9 (#221), Solar Pro4: 38.8 (#128)

BenchmarkGrok 4.1 FastSolar Pro4
LMArena Math14081416
MathArena Final-Answer Competitions60.9%—
ProofBench4%—

Knowledge Solar Pro4 leads

Grok 4.1 Fast: 33.1 (#207), Solar Pro4: 39.8 (#129)

BenchmarkGrok 4.1 FastSolar Pro4
LMArena Expert13991427
Vectara Hallucination Rate17.8%—

Multimodal Not comparable

Grok 4.1 Fast: 37.0 (#76), Solar Pro4: —

BenchmarkGrok 4.1 FastSolar Pro4
LMArena Vision1201—

Multilingual Grok 4.1 Fast leads

Grok 4.1 Fast: 51.0 (#114), Solar Pro4: 48.7 (#139)

BenchmarkGrok 4.1 FastSolar Pro4
LMArena Non-English13911361
LMArena Chinese14411415
LMArena French14151397
LMArena German14041364
LMArena Japanese13491309
LMArena Korean13611382
LMArena Russian13871360
LMArena Spanish14131401

Instruction Following Too close to call

Grok 4.1 Fast: 72.7 (#133), Solar Pro4: 72.7 (#132)

BenchmarkGrok 4.1 FastSolar Pro4
LMArena Instruction Following13761377

Long Context Too close to call

Grok 4.1 Fast: 42.4 (#126), Solar Pro4: 42.1 (#130)

BenchmarkGrok 4.1 FastSolar Pro4
LMArena Longer Query13901381

Writing & Preference Too close to call

Grok 4.1 Fast: 57.2 (#131), Solar Pro4: 56.5 (#138)

BenchmarkGrok 4.1 FastSolar Pro4
LMArena Text14081386
LMArena Creative Writing13941316
LMArena Multi-Turn13891385
EQ-Bench Creative Writing1327—

Frequently asked questions

Is Grok 4.1 Fast better than Solar Pro4?

Grok 4.1 Fast and Solar Pro4 score almost the same on the Noometry Index (41.4 vs 42.1), so choose on price, context window or the category you care about most.

Which is cheaper, Grok 4.1 Fast or Solar Pro4?

Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Solar Pro4 lists at $0.30 and $1.20.

Is Grok 4.1 Fast or Solar Pro4 better for coding?

Solar Pro4 scores higher on coding benchmarks: 40.1 versus 34.1 in the Noometry coding category.

Which has the bigger context window?

Solar Pro4 does, with 524K tokens against 128K.

How many benchmarks do Grok 4.1 Fast and Solar Pro4 share?

18 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and Solar Pro4 has 18.

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