Model comparison

GPT-5.6 Terra vs Solar Pro4

GPT-5.6 Terra is the stronger model overall, scoring 59.2 to 42.1 on the Noometry Index. Solar Pro4 costs 8.6× less per token, which makes it the better buy when GPT-5.6 Terra's lead doesn't matter for your workload.

Last verified . 18 shared benchmarks.

GPT-5.6 Terra OpenAI

59.2

Rank #17 Confirmed

Solar Pro4 Upstage

42.1

Rank #121 Confirmed

Summary

  • They share 18 benchmarks with published results for both. GPT-5.6 Terra 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-5.6 Terra leads 81.6 to 38.8.
  • Solar Pro4 is cheaper at $0.30 / $1.20 per million input/output tokens, against $2 / $12 for GPT-5.6 Terra.
  • GPT-5.6 Terra accepts more context: 1.05M tokens versus 524K.

Side by side

GPT-5.6 Terra and Solar Pro4 specifications
GPT-5.6 TerraSolar Pro4
ProviderOpenAIUpstage
Noometry Index59.242.1
Released2026-07-092026-08-06
WeightsProprietaryProprietary
Context window1.05M524K
Max output128K131K
Input $ / M tokens$2$0.30
Output $ / M tokens$12$1.20
Results tracked5218

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Category by category

Coding GPT-5.6 Terra leads

GPT-5.6 Terra: 57.7 (#19), Solar Pro4: 40.1 (#149)

Coding benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
LMArena WebDev15221371
LMArena Coding14841437
DeepSWE69.6%—
FrontierCode41.3%—
CursorBench41.3%—
SciCode55%—
WeirdML78.3%—
ALE-Bench1,951—

Agentic & Tool Use Not comparable

GPT-5.6 Terra: 40.1 (#25), Solar Pro4: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
APEX-Agents58.2%—
BALROG53.2%—
GDP.pdf24.7%—
Vending-Bench 27,343—

Reasoning GPT-5.6 Terra leads

GPT-5.6 Terra: 60.7 (#21), Solar Pro4: 28.5 (#104)

Reasoning benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
LMArena Hard Prompts14681399
ARC-AGI-283.9%—
SimpleBench48.9%—
Kagi LLM Benchmark51.3%—
NYT Connections (extended)78.4%—
ARC-AGI-196.5%—
CritPt30%—
Chess Puzzles54%—
Mystery Game Puzzles35%—
DTBench93.3%—
LMCA55%—
Surface Evolver Bench83.8%—
Epoch Capabilities Index159.62—

Math GPT-5.6 Terra leads

GPT-5.6 Terra: 81.6 (#12), Solar Pro4: 38.8 (#128)

Math benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
LMArena Math14661416
FrontierMath (Tiers 1-3)86%—
FrontierMath Tier 470.7%—
OTIS Mock AIME 2024-202599.7%—
ProofBench74%—

Knowledge GPT-5.6 Terra leads

GPT-5.6 Terra: 61.2 (#30), Solar Pro4: 39.8 (#129)

Knowledge benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
LMArena Expert14921427
GPQA Diamond93.3%—
SimpleQA Verified43.2%—

Multimodal Not comparable

GPT-5.6 Terra: 47.3 (#11), Solar Pro4: —

Multimodal benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
LMArena Vision1271—
Blueprint-Bench 230.8%—
Furniture Assembly54.2%—
LMArena Document1472—

Multilingual GPT-5.6 Terra leads

GPT-5.6 Terra: 54.4 (#44), Solar Pro4: 48.7 (#139)

Multilingual benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
LMArena Non-English14391361
LMArena Chinese15131415
LMArena French14711397
LMArena German14601364
LMArena Japanese14571309
LMArena Korean14251382
LMArena Russian14501360
LMArena Spanish14481401

Instruction Following GPT-5.6 Terra leads

GPT-5.6 Terra: 76.4 (#40), Solar Pro4: 72.7 (#132)

Instruction Following benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
LMArena Instruction Following14541377

Long Context GPT-5.6 Terra leads

GPT-5.6 Terra: 44.4 (#68), Solar Pro4: 42.1 (#130)

Long Context benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
LMArena Longer Query14511381

Writing & Preference GPT-5.6 Terra leads

GPT-5.6 Terra: 70.2 (#23), Solar Pro4: 56.5 (#138)

Writing & Preference benchmarks
BenchmarkGPT-5.6 TerraSolar Pro4
LMArena Text14471386
LMArena Creative Writing14101316
LMArena Multi-Turn14491385
EQ-Bench Creative Writing1855—
EQ-Bench 41234—

Frequently asked questions

Is GPT-5.6 Terra better than Solar Pro4?

GPT-5.6 Terra is the stronger model overall, scoring 59.2 to 42.1 on the Noometry Index. Solar Pro4 costs 8.6× less per token, which makes it the better buy when GPT-5.6 Terra's lead doesn't matter for your workload.

Which is cheaper, GPT-5.6 Terra or Solar Pro4?

Solar Pro4 is cheaper. It lists at $0.30 per million input tokens and $1.20 per million output tokens; GPT-5.6 Terra lists at $2 and $12.

Is GPT-5.6 Terra or Solar Pro4 better for coding?

GPT-5.6 Terra scores higher on coding benchmarks: 57.7 versus 40.1 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Terra does, with 1.05M tokens against 524K.

How many benchmarks do GPT-5.6 Terra and Solar Pro4 share?

18 benchmarks have published results for both models. GPT-5.6 Terra has 52 scored results on Noometry and Solar Pro4 has 18.

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