Noometry

Model comparison

GPT-5.3 Chat vs Llama 3.1-405B

GPT-5.3 Chat is the stronger model overall, scoring 42.8 to 30.7 on the Noometry Index.

Last verified . 18 shared benchmarks.

GPT-5.3 Chat OpenAI

42.8

Rank #109 Confirmed

Llama 3.1-405B Meta

30.7

Rank #288 Confirmed

Summary

  • They share 18 benchmarks with published results for both. GPT-5.3 Chat scores higher in 8 categories and Llama 3.1-405B in 0 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in writing & preference, where GPT-5.3 Chat leads 63.1 to 38.9.
  • Llama 3.1-405B has downloadable open weights; the other is API-only.

Side by side

GPT-5.3 ChatLlama 3.1-405B
ProviderOpenAIMeta
Noometry Index42.830.7
Released2026-03-032024-07-23
WeightsProprietaryOpen
Context window128K—
Max output16K—
Input $ / M tokens$1.75—
Output $ / M tokens$14—
Results tracked1842

Sponsored placements are available on pages like this one. Advertise on Noometry

Category by category

Coding GPT-5.3 Chat leads

GPT-5.3 Chat: 41.4 (#124), Llama 3.1-405B: 33.1 (#262)

BenchmarkGPT-5.3 ChatLlama 3.1-405B
LMArena Coding14081291
WeirdML—21.4%

Agentic & Tool Use Not comparable

GPT-5.3 Chat: —, Llama 3.1-405B: 21.0 (#140)

BenchmarkGPT-5.3 ChatLlama 3.1-405B
TheAgentCompany—7.4%
Cybench—7.5%

Reasoning GPT-5.3 Chat leads

GPT-5.3 Chat: 28.5 (#102), Llama 3.1-405B: 16.8 (#300)

BenchmarkGPT-5.3 ChatLlama 3.1-405B
LMArena Hard Prompts13991269
SimpleBench—23%
Kagi LLM Benchmark—45%
DTBench—61.4%
BIG-Bench Hard—82.9%
Epoch Capabilities Index—128.75
ForecastBench—59.9
HellaSwag—89.2%
PIQA—85.9%
WinoGrande—89.2%

Math GPT-5.3 Chat leads

GPT-5.3 Chat: 38.2 (#142), Llama 3.1-405B: 18.4 (#290)

BenchmarkGPT-5.3 ChatLlama 3.1-405B
LMArena Math13891281
OTIS Mock AIME 2024-2025—9.7%
Omni-MATH—24.9%
MATH Level 5—49.8%

Knowledge GPT-5.3 Chat leads

GPT-5.3 Chat: 38.8 (#140), Llama 3.1-405B: 30.4 (#227)

BenchmarkGPT-5.3 ChatLlama 3.1-405B
LMArena Expert13971243
GPQA Diamond—50.9%
MMLU-Pro—72.3%
Confabulations—17.6%
GPQA (HELM)—52.2%
ARC (AI2) Challenge—95.3%
MMLU—84.5%
TriviaQA—82.7%

Multilingual GPT-5.3 Chat leads

GPT-5.3 Chat: 50.3 (#124), Llama 3.1-405B: 40.7 (#214)

BenchmarkGPT-5.3 ChatLlama 3.1-405B
LMArena Non-English13821248
LMArena Chinese14321242
LMArena French13971279
LMArena German13841252
LMArena Japanese13521208
LMArena Korean13461184
LMArena Russian14001265
LMArena Spanish13711260

Instruction Following GPT-5.3 Chat leads

GPT-5.3 Chat: 72.8 (#129), Llama 3.1-405B: 65.9 (#214)

BenchmarkGPT-5.3 ChatLlama 3.1-405B
LMArena Instruction Following13781259
IFEval—81.1%

Long Context GPT-5.3 Chat leads

GPT-5.3 Chat: 42.6 (#120), Llama 3.1-405B: 38.4 (#197)

BenchmarkGPT-5.3 ChatLlama 3.1-405B
LMArena Longer Query13961266

Writing & Preference GPT-5.3 Chat leads

GPT-5.3 Chat: 63.1 (#68), Llama 3.1-405B: 38.9 (#251)

BenchmarkGPT-5.3 ChatLlama 3.1-405B
LMArena Text13891284
LMArena Creative Writing13551262
EQ-Bench Creative Writing1690870
LMArena Multi-Turn14121297
WildBench—78.3%

Frequently asked questions

Is GPT-5.3 Chat better than Llama 3.1-405B?

GPT-5.3 Chat is the stronger model overall, scoring 42.8 to 30.7 on the Noometry Index.

Is GPT-5.3 Chat or Llama 3.1-405B better for coding?

GPT-5.3 Chat scores higher on coding benchmarks: 41.4 versus 33.1 in the Noometry coding category.

How many benchmarks do GPT-5.3 Chat and Llama 3.1-405B share?

18 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Llama 3.1-405B has 42.

Related comparisons

Go deeper