Head to head

GLM 5.3 vs Claude Fable 5.1

Claude Fable 5.1 scores higher on 4 of the 4 benchmarks both models publish. The widest gap is on Humanity's Last Exam, where Claude Fable 5.1 leads by 18.6 points. GLM 5.3 has open weights, so unlike Claude Fable 5.1 you can run it on your own GPU with no per-token fees.

GLM 5.3Z.ai (Zhipu) · Open weights82.7compositeClaude Fable 5.1Anthropic · Closed API91.2composite

Shared benchmarks

Raw published scores; the higher score on each row is highlighted. LMArena Elo is a human-preference vote and is not counted as a win.

  • GPQA Diamond
    91.793.7

    GLM 5.3 (max); competitor comparison columnGPQA Diamond; AA independent run (Max, Default Fallback)

  • Humanity's Last Exam
    42.360.9

    no tools, text-only subset (2,158 q); competitor comparison columnHumanity's Last Exam, no tools; max effort

  • Humanity's Last Exam (with tools)
    62.565.0

    with toolsHumanity's Last Exam, with tools; max effort (Opus 5.5 system card lists Fable 5.1 at 65.6%)

  • Terminal-Bench 4.0
    41.955.8

    Terminal-Bench 4, Max, mini-swe-agent harnessTerminal-Bench 4.0; max effort, Claude Code --bare, 15 trials/task (Mythos 5.1 scored 60.9%)

  • LMArena Text Elo · not counted
    14811504

    GLM-5.3 (Max), ±5, board dated 2026-10-27LMArena Text, Overall; snapshot Oct 27, 2026; Claude Fable 5.1 (Max); +/-6

Should you pick GLM 5.3 or Claude Fable 5.1?

Pick GLM 5.3 if…

  • You need to self-host: keep prompts and data on your own GPU, avoid per-token fees, or fine-tune the weights.
  • Cost matters: $4.40 per million output tokens against $50.00.

Pick Claude Fable 5.1 if…

  • You care most about GPQA Diamond, Humanity's Last Exam, Humanity's Last Exam (with tools), where it scores at least 2 points higher.
  • You want a managed API and would rather not run or pay for GPUs yourself.
  • People prefer its answers in blind chats: LMArena Elo 1504 against 1481.

Hardware and cost to run

GLM 5.3

Even at 4-bit it needs about 520 GB (4× H200 (564 GB)), well beyond a home workstation, so most people run it on rented multi-GPU servers. Full BF16 precision needs about 1.7 TB (Multiple nodes (over 1.1 TB)).

Full GPU memory table for GLM 5.3

Claude Fable 5.1

Claude Fable 5.1 is only available through Anthropic's API, so it cannot be self-hosted; it costs $10 per million input tokens and $50 per million output tokens.

Category profile

Category index uses every test each model reports, not only the shared ones.

ReasoningCodingAgenticKnowledge
GLM 5.3Claude Fable 5.1
Reasoning80.696.1
Coding78.384.7
Agentic89.392.9
Knowledge——

Specs side by side

GLM 5.3Claude Fable 5.1
LabZ.ai (Zhipu)Anthropic
WeightsOpenAPI only
Released2026-08-142026-09-01
Parameters753B total, 40B active (MoE)—
Context1M1M
LicenseGLM-5.3 License (custom; arena.ai lists MIT)—
4-bit memory520 GB · 4× H200 (564 GB)—
API price$1.40 in / $4.40 out per 1M tokens$10.00 in / $50.00 out per 1M tokens
API speed88 tok/s71 tok/s

Related comparisons

Sources

ModelTestScoreSettingSource
GLM 5.3GPQA Diamond91.7GLM 5.3 (max); competitor comparison columnMeta Muse Spark Open model card (comparison column)
Claude Fable 5.1GPQA Diamond93.7GPQA Diamond; AA independent run (Max, Default Fallback)Artificial Analysis
GLM 5.3Humanity's Last Exam42.3no tools, text-only subset (2,158 q); competitor comparison columnMiniMax M3.1 Flash model card (comparison column)
Claude Fable 5.1Humanity's Last Exam60.9Humanity's Last Exam, no tools; max effortAnthropic Claude Fable 5.1 / Mythos 5.1 System Card (Table 8.1.A)
GLM 5.3Humanity's Last Exam (with tools)62.5with toolsHugging Face model card (GLM-5.3)
Claude Fable 5.1Humanity's Last Exam (with tools)65.0Humanity's Last Exam, with tools; max effort (Opus 5.5 system card lists Fable 5.1 at 65.6%)Anthropic Claude Fable 5.1 / Mythos 5.1 System Card (Table 8.1.A)
GLM 5.3Terminal-Bench 4.041.9Terminal-Bench 4, Max, mini-swe-agent harnessHugging Face model card (GLM-5.3), evaluation results
Claude Fable 5.1Terminal-Bench 4.055.8Terminal-Bench 4.0; max effort, Claude Code --bare, 15 trials/task (Mythos 5.1 scored 60.9%)Anthropic Claude Fable 5.1 / Mythos 5.1 System Card (sec 8.6)
GLM 5.3LMArena Text Elo1481GLM-5.3 (Max), ±5, board dated 2026-10-27LMArena (arena.ai) text leaderboard
Claude Fable 5.1LMArena Text Elo1504LMArena Text, Overall; snapshot Oct 27, 2026; Claude Fable 5.1 (Max); +/-6LMArena (arena.ai) Text leaderboard

Scores are published results from model cards, lab reports, and public leaderboards, each linked to its source. Settings such as thinking mode or test version differ between sources and are shown next to each score. OpenLLM Buddy catalog models are uncensored fine-tunes; their scores are those of the official base model. Data collected 2026-10-30. How the index works