Model comparison

GPT-5.3 Codex vs Solar Pro4

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 42.1 on the Noometry Index. Solar Pro4 costs 9.2× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.

Last verified . 1 shared benchmarks.

GPT-5.3 Codex OpenAI

45.8

Rank #69 Reported

Solar Pro4 Upstage

42.1

Rank #121 Confirmed

Summary

  • They share 1 benchmark with published results for both. GPT-5.3 Codex scores higher in 1 category and Solar Pro4 in 0 categories; one gap is clear of the uncertainty.
  • The widest gap is in coding, where GPT-5.3 Codex leads 48.6 to 40.1.
  • Solar Pro4 is cheaper at $0.30 / $1.20 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
  • Solar Pro4 accepts more context: 524K tokens versus 400K.

Side by side

GPT-5.3 Codex and Solar Pro4 specifications
GPT-5.3 CodexSolar Pro4
ProviderOpenAIUpstage
Noometry Index45.842.1
Released2026-02-052026-08-06
WeightsProprietaryProprietary
Context window400K524K
Max output128K131K
Input $ / M tokens$1.75$0.30
Output $ / M tokens$14$1.20
Results tracked818

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Category by category

Coding GPT-5.3 Codex leads

GPT-5.3 Codex: 48.6 (#56), Solar Pro4: 40.1 (#149)

Coding benchmarks
BenchmarkGPT-5.3 CodexSolar Pro4
LMArena WebDev14091371
SWE-bench Verified74.8%—
WeirdML79.3%—
LMArena Coding—1437
ALE-Bench1,655—

Agentic & Tool Use Not comparable

GPT-5.3 Codex: 48.0 (#9), Solar Pro4: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.3 CodexSolar Pro4
Terminal-Bench78.4%—
METR Time Horizons74.5%—
Vending-Bench 25,940—

Reasoning Not comparable

GPT-5.3 Codex: —, Solar Pro4: 28.5 (#104)

Reasoning benchmarks
BenchmarkGPT-5.3 CodexSolar Pro4
LMArena Hard Prompts—1399
Epoch Capabilities Index156.77—

Math Not comparable

GPT-5.3 Codex: —, Solar Pro4: 38.8 (#128)

Math benchmarks
BenchmarkGPT-5.3 CodexSolar Pro4
LMArena Math—1416

Knowledge Not comparable

GPT-5.3 Codex: —, Solar Pro4: 39.8 (#129)

Knowledge benchmarks
BenchmarkGPT-5.3 CodexSolar Pro4
LMArena Expert—1427

Multilingual Not comparable

GPT-5.3 Codex: —, Solar Pro4: 48.7 (#139)

Multilingual benchmarks
BenchmarkGPT-5.3 CodexSolar Pro4
LMArena Non-English—1361
LMArena Chinese—1415
LMArena French—1397
LMArena German—1364
LMArena Japanese—1309
LMArena Korean—1382
LMArena Russian—1360
LMArena Spanish—1401

Instruction Following Not comparable

GPT-5.3 Codex: —, Solar Pro4: 72.7 (#132)

Instruction Following benchmarks
BenchmarkGPT-5.3 CodexSolar Pro4
LMArena Instruction Following—1377

Long Context Not comparable

GPT-5.3 Codex: —, Solar Pro4: 42.1 (#130)

Long Context benchmarks
BenchmarkGPT-5.3 CodexSolar Pro4
LMArena Longer Query—1381

Writing & Preference Not comparable

GPT-5.3 Codex: —, Solar Pro4: 56.5 (#138)

Writing & Preference benchmarks
BenchmarkGPT-5.3 CodexSolar Pro4
LMArena Text—1386
LMArena Creative Writing—1316
LMArena Multi-Turn—1385

Frequently asked questions

Is GPT-5.3 Codex better than Solar Pro4?

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 42.1 on the Noometry Index. Solar Pro4 costs 9.2× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.

Which is cheaper, GPT-5.3 Codex or Solar Pro4?

Solar Pro4 is cheaper. It lists at $0.30 per million input tokens and $1.20 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.

Is GPT-5.3 Codex or Solar Pro4 better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.6 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-5.3 Codex and Solar Pro4 share?

1 benchmark has published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Solar Pro4 has 18.

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