Model comparison

GPT-5.1 vs Llama 3.1-8B

GPT-5.1 is the stronger model overall, scoring 48.8 to 22.8 on the Noometry Index. Llama 3.1-8B costs 60× less per token, which makes it the better buy when GPT-5.1's lead doesn't matter for your workload.

Last verified . 31 shared benchmarks.

GPT-5.1 OpenAI

48.8

Rank #47 Confirmed

Llama 3.1-8B Meta

22.8

Rank #347 Confirmed

Summary

  • They share 31 benchmarks with published results for both. GPT-5.1 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-5.1 leads 50.5 to 8.0.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 88.6% for GPT-5.1 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-5.1.
  • GPT-5.1 accepts more context: 400K tokens versus 128K.
  • Llama 3.1-8B has downloadable open weights; the other is API-only.

Side by side

GPT-5.1 and Llama 3.1-8B specifications
GPT-5.1Llama 3.1-8B
ProviderOpenAIMeta
Noometry Index48.822.8
Released2025-11-132024-07-23
WeightsProprietaryOpen
Context window400K128K
Max output128K4K
Input $ / M tokens$1.25$0.05
Output $ / M tokens$10$0.08
Results tracked6343

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Category by category

Coding GPT-5.1 leads

GPT-5.1: 46.9 (#59), Llama 3.1-8B: 19.9 (#335)

Coding benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
SciCode43.3%13.2%
WeirdML60.8%1.7%
LMArena Coding14541195
SWE-bench Verified68%—
SWE-bench Verified (bash only)66%—
LMArena WebDev1395—
GSO13.7%—
BigCodeBench Instruct—32.8%
LiveBench Coding72.5%—
BigCodeBench Complete—40.5%
ALE-Bench1,192—
HumanEval+—62.8%
MBPP+—55.6%

Agentic & Tool Use GPT-5.1 leads

GPT-5.1: 32.5 (#55), Llama 3.1-8B: 22.3 (#123)

Agentic & Tool Use benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
Terminal-Bench47.6%—
Berkeley Function Calling Leaderboard—25.8%
DeepResearch Bench42.8%—
BALROG—15.1%
LMArena Search1199—
Vending-Bench 21,473—

Reasoning GPT-5.1 leads

GPT-5.1: 39.9 (#50), Llama 3.1-8B: 14.5 (#316)

Reasoning benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
CritPt4.9%0%
Chess Puzzles32%0%
LMArena Hard Prompts14571175
DTBench90.1%50.9%
LMCA43.9%5.4%
Epoch Capabilities Index149.66116.48
ARC-AGI-217.6%—
SimpleBench53.2%—
ARC-AGI-172.8%—
EnigmaEval11.2%—
LiveBench Reasoning95.8%—
Mystery Game Puzzles19%—
LiveBench Data Analysis72.1%—
ForecastBench58.1—
LiveBench78.8%—
PIQA—81.2%

Math GPT-5.1 leads

GPT-5.1: 50.3 (#45), Llama 3.1-8B: 9.5 (#311)

Math benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
OTIS Mock AIME 2024-202588.6%1.7%
Omni-MATH46.4%13.7%
LMArena Math14461179
LiveBench Math94.5%—
MATH Level 5—22.9%
FrontierMath (Feb 2025 set)31%—
FrontierMath Tier 4 (v1)12.5%—
GSM8K—82.4%

Knowledge GPT-5.1 leads

GPT-5.1: 50.5 (#65), Llama 3.1-8B: 8.0 (#302)

Knowledge benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
GPQA Diamond87.6%27%
MMLU-Pro57.9%40.6%
GPQA (HELM)44.2%24.7%
LMArena Expert14701144
Humanity's Last Exam23.7%—
SimpleQA Verified48%—
Vectara Hallucination Rate10.9%—
BoolQ—82.8%
MMLU—56.1%

Multimodal Not comparable

GPT-5.1: 44.0 (#17), Llama 3.1-8B: —

Multimodal benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
LMArena Vision1250—
VPCT58.7%—
LMArena Document1403—

Multilingual GPT-5.1 leads

GPT-5.1: 54.0 (#51), Llama 3.1-8B: 34.2 (#244)

Multilingual benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
LMArena Non-English14311148
LMArena Chinese14951151
LMArena French14511176
LMArena German14391144
LMArena Japanese14531061
LMArena Korean14011053
LMArena Russian14351158
LMArena Spanish14301169

Instruction Following GPT-5.1 leads

GPT-5.1: 84.0 (#1), Llama 3.1-8B: 59.1 (#253)

Instruction Following benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
IFEval93.5%74.3%
LMArena Instruction Following14421159
LiveBench Instruction Following93.3%—

Long Context GPT-5.1 leads

GPT-5.1: 47.6 (#14), Llama 3.1-8B: 35.8 (#233)

Long Context benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
LMArena Longer Query14481182
CL-bench23.7%—
CL-bench Life17.3%—

Writing & Preference GPT-5.1 leads

GPT-5.1: 64.7 (#53), Llama 3.1-8B: 29.9 (#285)

Writing & Preference benchmarks
BenchmarkGPT-5.1Llama 3.1-8B
LMArena Text14431187
LMArena Creative Writing14271154
WildBench86.3%68.7%
LMArena Multi-Turn14491172
EQ-Bench Creative Writing—713
LiveBench Language80.2%—

Frequently asked questions

Is GPT-5.1 better than Llama 3.1-8B?

GPT-5.1 is the stronger model overall, scoring 48.8 to 22.8 on the Noometry Index. Llama 3.1-8B costs 60× less per token, which makes it the better buy when GPT-5.1's lead doesn't matter for your workload.

Which is cheaper, GPT-5.1 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-5.1 lists at $1.25 and $10.

Is GPT-5.1 or Llama 3.1-8B better for coding?

GPT-5.1 scores higher on coding benchmarks: 46.9 versus 19.9 in the Noometry coding category.

Which has the bigger context window?

GPT-5.1 does, with 400K tokens against 128K.

How many benchmarks do GPT-5.1 and Llama 3.1-8B share?

31 benchmarks have published results for both models. GPT-5.1 has 63 scored results on Noometry and Llama 3.1-8B has 43.

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