Model comparison

GPT-5.3 Chat vs Solar Pro4

GPT-5.3 Chat and Solar Pro4 score almost the same on the Noometry Index (42.8 vs 42.1), so choose on price, context window or the category you care about most.

Last verified October 10, 2026. 17 shared benchmarks.

GPT-5.3 Chat OpenAI

42.8

Rank #109 Confirmed

Solar Pro4

Upstage

42.1

Rank #121 Confirmed

Summary

They share 17 benchmarks with published results for both. GPT-5.3 Chat scores higher in 6 categories and Solar Pro4 in 2 categories; 3 gaps are clear of the uncertainty.
The widest gap is in writing & preference, where GPT-5.3 Chat leads 63.1 to 56.5.
Solar Pro4 is cheaper at $0.30 / $1.20 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Chat.
Solar Pro4 accepts more context: 524K tokens versus 128K.

Side by side

GPT-5.3 Chat and Solar Pro4 specifications
	GPT-5.3 Chat	Solar Pro4
Provider	OpenAI	Upstage
Noometry Index	42.8	42.1
Released	2026-03-03	2026-08-06
Weights	Proprietary	Proprietary
Context window	128K	524K
Max output	16K	131K
Input $ / M tokens	$1.75	$0.30
Output $ / M tokens	$14	$1.20
Results tracked	18	18

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Category by category

Coding GPT-5.3 Chat leads

GPT-5.3 Chat: 41.4 (#124), Solar Pro4: 40.1 (#149)

Coding benchmarks
Benchmark	GPT-5.3 Chat	Solar Pro4
LMArena Coding	1408	1437
LMArena WebDev	—	1371

Reasoning Too close to call

GPT-5.3 Chat: 28.5 (#102), Solar Pro4: 28.5 (#104)

Reasoning benchmarks
Benchmark	GPT-5.3 Chat	Solar Pro4
LMArena Hard Prompts	1399	1399

Math Too close to call

GPT-5.3 Chat: 38.2 (#142), Solar Pro4: 38.8 (#128)

Math benchmarks
Benchmark	GPT-5.3 Chat	Solar Pro4
LMArena Math	1389	1416

Knowledge Too close to call

GPT-5.3 Chat: 38.8 (#140), Solar Pro4: 39.8 (#129)

Knowledge benchmarks
Benchmark	GPT-5.3 Chat	Solar Pro4
LMArena Expert	1397	1427

Multilingual GPT-5.3 Chat leads

GPT-5.3 Chat: 50.3 (#124), Solar Pro4: 48.7 (#139)

Multilingual benchmarks
Benchmark	GPT-5.3 Chat	Solar Pro4
LMArena Non-English	1382	1361
LMArena Chinese	1432	1415
LMArena French	1397	1397
LMArena German	1384	1364
LMArena Japanese	1352	1309
LMArena Korean	1346	1382
LMArena Russian	1400	1360
LMArena Spanish	1371	1401

Instruction Following Too close to call

GPT-5.3 Chat: 72.8 (#129), Solar Pro4: 72.7 (#132)

Instruction Following benchmarks
Benchmark	GPT-5.3 Chat	Solar Pro4
LMArena Instruction Following	1378	1377

Long Context Too close to call

GPT-5.3 Chat: 42.6 (#120), Solar Pro4: 42.1 (#130)

Long Context benchmarks
Benchmark	GPT-5.3 Chat	Solar Pro4
LMArena Longer Query	1396	1381

Writing & Preference GPT-5.3 Chat leads

GPT-5.3 Chat: 63.1 (#68), Solar Pro4: 56.5 (#138)

Writing & Preference benchmarks
Benchmark	GPT-5.3 Chat	Solar Pro4
LMArena Text	1389	1386
LMArena Creative Writing	1355	1316
LMArena Multi-Turn	1412	1385
EQ-Bench Creative Writing	1690	—

Frequently asked questions

Is GPT-5.3 Chat better than Solar Pro4?

GPT-5.3 Chat and Solar Pro4 score almost the same on the Noometry Index (42.8 vs 42.1), so choose on price, context window or the category you care about most.

Which is cheaper, GPT-5.3 Chat 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 Chat lists at $1.75 and $14.

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

GPT-5.3 Chat scores higher on coding benchmarks: 41.4 versus 40.1 in the Noometry coding category.

Which has the bigger context window?

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

How many benchmarks do GPT-5.3 Chat and Solar Pro4 share?

17 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Solar Pro4 has 18.