Model comparison

GPT-5 vs Llama 3.1-8B

GPT-5 is the stronger model overall, scoring 50.9 to 23.0 on the Noometry Index. Llama 3.1-8B costs 60× less per token, which makes it the better buy when GPT-5's lead doesn't matter for your workload.

Last verified . 34 shared benchmarks.

GPT-5 OpenAI

50.9

Rank #45 Confirmed

Llama 3.1-8B Meta

23.0

Rank #352 Confirmed

Summary

  • They share 34 benchmarks with published results for both. GPT-5 scores higher in 9 categories and Llama 3.1-8B in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where GPT-5 leads 56.6 to 8.0.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 91.4% for GPT-5 and 1.7% for Llama 3.1-8B.
  • Llama 3.1-8B is cheaper at $0.05 / $0.08 per million input/output tokens, against $1.25 / $10 for GPT-5.
  • GPT-5 accepts more context: 400K tokens versus 128K.
  • Llama 3.1-8B has downloadable open weights; the other is API-only.

Side by side

GPT-5 and Llama 3.1-8B specifications
GPT-5Llama 3.1-8B
ProviderOpenAIMeta
Noometry Index50.923.0
Released2025-08-072024-07-23
WeightsProprietaryOpen
Context window400K128K
Max output128K4K
Input $ / M tokens$1.25$0.05
Output $ / M tokens$10$0.08
Results tracked6943

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Category by category

Coding GPT-5 leads

GPT-5: 50.3 (#47), Llama 3.1-8B: 20.2 (#340)

Coding benchmarks
BenchmarkGPT-5Llama 3.1-8B
SciCode42.9%13.2%
WeirdML60.7%1.7%
LMArena Coding14361195
SWE-bench Verified73.6%—
SWE-bench Verified (bash only)65%—
Aider Polyglot88%—
LMArena WebDev1418—
GSO6.9%—
BigCodeBench Instruct—32.8%
BigCodeBench Complete—40.5%
ALE-Bench1,162—
AlgoTune1.67—
HumanEval+—62.8%
MBPP+—55.6%

Agentic & Tool Use GPT-5 leads

GPT-5: 33.1 (#56), Llama 3.1-8B: 22.5 (#131)

Agentic & Tool Use benchmarks
BenchmarkGPT-5Llama 3.1-8B
BALROG32.8%15.1%
Terminal-Bench49.6%—
Berkeley Function Calling Leaderboard—25.8%
GDPval34.8%—
Remote Labor Index1.7%—
DeepResearch Bench49.6%—
LMArena Search1133—
METR Time Horizons69.6%—

Reasoning GPT-5 leads

GPT-5: 38.3 (#64), Llama 3.1-8B: 14.9 (#321)

Reasoning benchmarks
BenchmarkGPT-5Llama 3.1-8B
CritPt12.6%0%
Chess Puzzles37%0%
LMArena Hard Prompts14161175
DTBench90.7%50.9%
LMCA40%5.4%
Epoch Capabilities Index150116.57
ARC-AGI-29.9%—
SimpleBench56.7%—
Kagi LLM Benchmark72.7%—
ARC-AGI-165.7%—
EnigmaEval10.5%—
EBR-Bench12.7%—
Mystery Game Puzzles23%—
ForecastBench61.4—
PIQA—81.2%

Math GPT-5 leads

GPT-5: 55.0 (#44), Llama 3.1-8B: 10.2 (#317)

Math benchmarks
BenchmarkGPT-5Llama 3.1-8B
OTIS Mock AIME 2024-202591.4%1.7%
Omni-MATH64.7%13.7%
LMArena Math14071179
MATH Level 598.1%22.9%
FrontierMath (Tiers 1-3)55.4%—
FrontierMath Tier 422%—
ProofBench18%—
FrontierMath (Feb 2025 set)32.4%—
FrontierMath Tier 4 (v1)12.5%—
GSM8K—82.4%

Knowledge GPT-5 leads

GPT-5: 56.6 (#43), Llama 3.1-8B: 8.0 (#307)

Knowledge benchmarks
BenchmarkGPT-5Llama 3.1-8B
GPQA Diamond86.2%27%
MMLU-Pro86.3%40.6%
GPQA (HELM)79.2%24.7%
LMArena Expert14191144
Humanity's Last Exam25.3%—
SimpleQA Verified50.1%—
Confabulations10.3%—
Vectara Hallucination Rate14.7%—
BoolQ—82.8%
MMLU—56.1%

Multimodal Not comparable

GPT-5: 46.8 (#13), Llama 3.1-8B: —

Multimodal benchmarks
BenchmarkGPT-5Llama 3.1-8B
LMArena Vision1232—
GeoBench81%—
VPCT66%—

Multilingual GPT-5 leads

GPT-5: 51.4 (#110), Llama 3.1-8B: 34.0 (#249)

Multilingual benchmarks
BenchmarkGPT-5Llama 3.1-8B
LMArena Non-English13971148
LMArena Chinese14221151
LMArena French14101177
LMArena German14161144
LMArena Japanese14091061
LMArena Korean13601053
LMArena Russian14061158
LMArena Spanish13991169

Instruction Following GPT-5 leads

GPT-5: 73.8 (#113), Llama 3.1-8B: 58.9 (#258)

Instruction Following benchmarks
BenchmarkGPT-5Llama 3.1-8B
IFEval87.5%74.3%
LMArena Instruction Following13881159

Long Context GPT-5 leads

GPT-5: 69.5 (#2), Llama 3.1-8B: 35.8 (#238)

Long Context benchmarks
BenchmarkGPT-5Llama 3.1-8B
LMArena Longer Query13991182
Fiction.LiveBench97.2%—

Writing & Preference GPT-5 leads

GPT-5: 63.4 (#65), Llama 3.1-8B: 29.7 (#290)

Writing & Preference benchmarks
BenchmarkGPT-5Llama 3.1-8B
LMArena Text14061187
LMArena Creative Writing13651154
EQ-Bench Creative Writing1627713
WildBench85.7%68.7%
LMArena Multi-Turn14261172
Short-Story Creative Writing86%—

Frequently asked questions

Is GPT-5 better than Llama 3.1-8B?

GPT-5 is the stronger model overall, scoring 50.9 to 23.0 on the Noometry Index. Llama 3.1-8B costs 60× less per token, which makes it the better buy when GPT-5's lead doesn't matter for your workload.

Which is cheaper, GPT-5 or Llama 3.1-8B?

Llama 3.1-8B is cheaper. It lists at $0.05 per million input tokens and $0.08 per million output tokens; GPT-5 lists at $1.25 and $10.

Is GPT-5 or Llama 3.1-8B better for coding?

GPT-5 scores higher on coding benchmarks: 50.3 versus 20.2 in the Noometry coding category.

Which has the bigger context window?

GPT-5 does, with 400K tokens against 128K.

How many benchmarks do GPT-5 and Llama 3.1-8B share?

34 benchmarks have published results for both models. GPT-5 has 69 scored results on Noometry and Llama 3.1-8B has 43.

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