Model comparison

GPT-5.1 vs Solar Pro4

GPT-5.1 is the stronger model overall, scoring 49.0 to 42.1 on the Noometry Index. Solar Pro4 costs 6.5× less per token, which makes it the better buy when GPT-5.1's lead doesn't matter for your workload.

Last verified . 18 shared benchmarks.

GPT-5.1 OpenAI

49.0

Rank #53 Confirmed

Solar Pro4 Upstage

42.1

Rank #121 Confirmed

Summary

  • They share 18 benchmarks with published results for both. GPT-5.1 scores higher in 8 categories and Solar Pro4 in 0 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.1 leads 52.2 to 38.8.
  • Solar Pro4 is cheaper at $0.30 / $1.20 per million input/output tokens, against $1.25 / $10 for GPT-5.1.
  • Solar Pro4 accepts more context: 524K tokens versus 400K.

Side by side

GPT-5.1 and Solar Pro4 specifications
GPT-5.1Solar Pro4
ProviderOpenAIUpstage
Noometry Index49.042.1
Released2025-11-132026-08-06
WeightsProprietaryProprietary
Context window400K524K
Max output128K131K
Input $ / M tokens$1.25$0.30
Output $ / M tokens$10$1.20
Results tracked6318

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Category by category

Coding GPT-5.1 leads

GPT-5.1: 46.4 (#66), Solar Pro4: 40.1 (#149)

Coding benchmarks
BenchmarkGPT-5.1Solar Pro4
LMArena WebDev13951371
LMArena Coding14541437
SWE-bench Verified68%—
SWE-bench Verified (bash only)66%—
SciCode43.3%—
GSO13.7%—
WeirdML60.8%—
LiveBench Coding72.5%—
ALE-Bench1,192—

Agentic & Tool Use Not comparable

GPT-5.1: 32.7 (#60), Solar Pro4: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.1Solar Pro4
Terminal-Bench47.6%—
DeepResearch Bench42.8%—
LMArena Search1199—
Vending-Bench 21,473—

Reasoning GPT-5.1 leads

GPT-5.1: 39.8 (#58), Solar Pro4: 28.5 (#104)

Reasoning benchmarks
BenchmarkGPT-5.1Solar Pro4
LMArena Hard Prompts14571399
ARC-AGI-217.6%—
SimpleBench53.2%—
ARC-AGI-172.8%—
CritPt4.9%—
Chess Puzzles32%—
EnigmaEval11.2%—
LiveBench Reasoning95.8%—
Mystery Game Puzzles19%—
DTBench90.1%—
LiveBench Data Analysis72.1%—
LMCA43.9%—
Epoch Capabilities Index149.64—
ForecastBench58.1—
LiveBench78.8%—

Math GPT-5.1 leads

GPT-5.1: 52.2 (#51), Solar Pro4: 38.8 (#128)

Math benchmarks
BenchmarkGPT-5.1Solar Pro4
LMArena Math14471416
OTIS Mock AIME 2024-202588.6%—
Omni-MATH46.4%—
LiveBench Math94.5%—
FrontierMath (Feb 2025 set)31%—
FrontierMath Tier 4 (v1)12.5%—

Knowledge GPT-5.1 leads

GPT-5.1: 50.6 (#71), Solar Pro4: 39.8 (#129)

Knowledge benchmarks
BenchmarkGPT-5.1Solar Pro4
LMArena Expert14701427
GPQA Diamond87.6%—
Humanity's Last Exam23.7%—
SimpleQA Verified48%—
MMLU-Pro57.9%—
Vectara Hallucination Rate10.9%—
GPQA (HELM)44.2%—

Multimodal Not comparable

GPT-5.1: 44.8 (#19), Solar Pro4: —

Multimodal benchmarks
BenchmarkGPT-5.1Solar Pro4
LMArena Vision1250—
VPCT58.7%—
LMArena Document1403—

Multilingual GPT-5.1 leads

GPT-5.1: 53.8 (#56), Solar Pro4: 48.7 (#139)

Multilingual benchmarks
BenchmarkGPT-5.1Solar Pro4
LMArena Non-English14311361
LMArena Chinese14951415
LMArena French14501397
LMArena German14381364
LMArena Japanese14531309
LMArena Korean14011382
LMArena Russian14351360
LMArena Spanish14331401

Instruction Following GPT-5.1 leads

GPT-5.1: 83.9 (#1), Solar Pro4: 72.7 (#132)

Instruction Following benchmarks
BenchmarkGPT-5.1Solar Pro4
LMArena Instruction Following14431377
LiveBench Instruction Following93.3%—
IFEval93.5%—

Long Context GPT-5.1 leads

GPT-5.1: 47.6 (#14), Solar Pro4: 42.1 (#130)

Long Context benchmarks
BenchmarkGPT-5.1Solar Pro4
LMArena Longer Query14471381
CL-bench23.7%—
CL-bench Life17.3%—

Writing & Preference GPT-5.1 leads

GPT-5.1: 64.5 (#55), Solar Pro4: 56.5 (#138)

Writing & Preference benchmarks
BenchmarkGPT-5.1Solar Pro4
LMArena Text14431386
LMArena Creative Writing14271316
LMArena Multi-Turn14501385
WildBench86.3%—
LiveBench Language80.2%—

Frequently asked questions

Is GPT-5.1 better than Solar Pro4?

GPT-5.1 is the stronger model overall, scoring 49.0 to 42.1 on the Noometry Index. Solar Pro4 costs 6.5× less per token, which makes it the better buy when GPT-5.1's lead doesn't matter for your workload.

Which is cheaper, GPT-5.1 or Solar Pro4?

Solar Pro4 is cheaper. It lists at $0.30 per million input tokens and $1.20 per million output tokens; GPT-5.1 lists at $1.25 and $10.

Is GPT-5.1 or Solar Pro4 better for coding?

GPT-5.1 scores higher on coding benchmarks: 46.4 versus 40.1 in the Noometry coding category.

Which has the bigger context window?

Solar Pro4 does, with 524K tokens against 400K.

How many benchmarks do GPT-5.1 and Solar Pro4 share?

18 benchmarks have published results for both models. GPT-5.1 has 63 scored results on Noometry and Solar Pro4 has 18.

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