Why is this comparison indexable?

It has 6 verifiable comparison points, and both models have pricing or benchmark data.

Are missing metrics invented?

No. Metrics without LMSpeed data are omitted from this report.

Back to models

Data points: 155

Model compare

GPT-5.4 vs GPT-5.6 Sol

The readout for GPT-5.4 and GPT-5.6 Sol, before the detailed comparison sheet.

Model A

GPT-5.4

OpenAI

Contender

Model B

GPT-5.6 Sol

OpenAI

Leading

Key Takeaways

Weighted outcome: GPT-5.6 Sol. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.

Decision read

GPT-5.6 Sol

GPT-5.6 Sol has the higher weighted result; Model A / B score 46.3 to 53.7.

Evidence depth

155 data points

Includes 45 benchmark rows, 0 audit samples, and 10 provider examples.

Selection signal

Start with GPT-5.6 Sol

The charts below split 55 high-signal samples across speed, scores, and audit health.

Change comparison

Switch either side of this report to compare another model with the same LMSpeed data pipeline.

Model AModel B

Comparison sheet

This report only uses LMSpeed data for GPT-5.4 and GPT-5.6 Sol: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.

Model compare	GPT-5.4	GPT-5.6 Sol
Overall leader	Contender	Leading
Weighted overall score	46.3 pts	53.7 pts
Benchmark category leads	3 categories	4 categories
Operational advantages	Cheapest input price, Free providers, Provider coverage	Average speed, First-token latency
Context window	1.1M tokens	1.1M tokens
Max output	128K tokens	128K tokens
Modalities	Input TextImageFile Output Text	Input FileImageText Output Text
Features	Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning	Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning

The overall result weights benchmark capability categories at 80% and price, API speed/latency, and availability at 20%. Recent test volume does not affect the winner, and missing benchmark categories are excluded.

Model metadata

Model compare	GPT-5.4	GPT-5.6 Sol
Developer	OpenAI	OpenAI
Released	Mar 2026	Jul 2026
Parameters	No data	No data
Tokenizer	GPT	GPT
Knowledge cutoff	No data	2026-02-16
OpenRouter ID	openai/gpt-5.4	openai/gpt-5.6-sol
References	No data	No data

When to choose each model

This report only uses LMSpeed data for GPT-5.4 and GPT-5.6 Sol: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.

GPT-5.4

GPT-5.4 is stronger in benchmark categories (Coding, Knowledge, Instruction following) and operational dimensions (Cheapest input price, Free providers, Provider coverage).

GPT-5.6 Sol

GPT-5.6 Sol is stronger in benchmark categories (Agents, Reasoning, Math, Multimodal) and operational dimensions (Average speed, First-token latency).

Benchmark score comparison

Third-party benchmark profile synced into LMSpeed; only metrics available for both models are shown.

Category performance

Compare benchmark category scores on a 0-100 scale. Select a category to inspect the gap.

Model A coverage: 7 / 8
Model B coverage: 7 / 8
Shared: 7 shared categories

Avg. score

GPT-5.4

56.6

Avg. score

GPT-5.6 Sol

60.2

Agents

GPT-5.6 Sol leads by 8.7

GPT-5.456.3

GPT-5.6 Sol65

Coding

GPT-5.4 leads by 1.4

GPT-5.462.2

GPT-5.6 Sol60.8

Reasoning

GPT-5.6 Sol leads by 5.2

GPT-5.455.7

GPT-5.6 Sol60.9

Knowledge

GPT-5.4 leads by 2.6

GPT-5.458.5

GPT-5.6 Sol55.9

Math

GPT-5.6 Sol leads by 9.2

GPT-5.456.8

GPT-5.6 Sol66

Multilingual

No data

GPT-5.4-

GPT-5.6 Sol-

Multimodal

GPT-5.6 Sol leads by 7.0

GPT-5.452.5

GPT-5.6 Sol59.5

Instruction following

GPT-5.4 leads by 0.5

GPT-5.454

GPT-5.6 Sol53.5

Professional benchmark details

Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.

Group

Aggregatereported

Provider	GPT-5.4	GPT-5.6 Sol
6345ywz API15 tests	GPT-5.4 speed / latency 41 tok/s / 6581ms input / output No data	GPT-5.6 Sol speed / latency N/A / N/A input / output No data
XShuLab Sub2API15 tests	GPT-5.4 speed / latency 24 tok/s / 2652ms input / output No data	GPT-5.6 Sol speed / latency N/A / N/A input / output No data
Fengsili API10 tests	GPT-5.4 speed / latency 88 tok/s / 6075ms input / output No data	GPT-5.6 Sol speed / latency N/A / N/A input / output No data
Omini Api10 tests	GPT-5.4 speed / latency 51 tok/s / 1443ms input / output No data	GPT-5.6 Sol speed / latency N/A / N/A input / output No data
VSLLM10 tests	GPT-5.4 speed / latency 60 tok/s / 2482ms input / output No data	GPT-5.6 Sol speed / latency 44 tok/s / 7130ms input / output No data
180txt API	GPT-5.4 gpt-5.4-2026-03-05 speed / latency No data input / output $0/M/$0/M	GPT-5.6 Sol gpt-5.6-sol-openai-compact speed / latency No data input / output $0.750/M/$4.50/M
APIMart	GPT-5.4 gpt-5.4 speed / latency No data input / output $0/M/$0/M	GPT-5.6 Sol gpt-5.6-sol speed / latency No data input / output $0/M/$0/M
Dext API	GPT-5.4 gpt-5-4 speed / latency No data input / output $0/M/$0/M	GPT-5.6 Sol gpt-5-6-sol speed / latency No data input / output $0/M/$0/M
兔子API	GPT-5.4 gpt-5.4-high speed / latency No data input / output $0/request	GPT-5.6 Sol gpt-5.6-sol speed / latency No data input / output $0/request
鲨鱼魔法	GPT-5.4 [mt]q\|次/gpt-5.4 speed / latency No data input / output $13.50/request	GPT-5.6 Sol [lq]t\|RS/gpt-5.6-sol speed / latency No data input / output $0/M/$0/M

Comparison sheet

Model metadata

When to choose each model

Benchmark score comparison

Category performance

Agents

Coding

Reasoning

Knowledge

Math

Multilingual

Multimodal

Instruction following

Professional benchmark details

BenchLM overall score

Input price

Blended price

Output price

CritPt

ARC-AGI-2

ARC-AGI-3

AA-LCR

GPQA

HLE

BenchLM Reasoning score

AA Coding Index

SWE-bench Pro

EEBench

AA-SciCode

BenchLM Coding score

BenchLM Math score

FrontierMath v2 (Tiers 1-3)

FrontierMath v2 (Tier 4)

Artificial Analysis Intelligence Index

HealthBench Hard

GPQA-D

HealthBench Professional

AA-GPQA Diamond

AA-HLE

AA-Omniscience Accuracy

BenchLM Knowledge score

AA-Omniscience Hallucination Rate

AA-Omniscience Index

MMMU-Pro w/ Python

MMMU-Pro

BenchLM Multimodal Grounded score

AA-MMMU-Pro

BenchLM Instruction Following score

AA-IFBench

BenchLM Agentic score

BrowseComp

CyberGym

Terminal-Bench 2.0

ExploitGym

τ²-bench results

Toolathlon

GDPval-AA

GDPval-AA

AA Agentic Index

API audit comparison

Provider examples

FAQ

Related compare reports