Claude Fable 5.1 vs GLM-5.3-Flash
Wins 8 of 8 areas
Coding · Agents · Reasoning · Facts · Images and charts · Math · Long documents · Following instructions
Wins 0 of 8 areas
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Claude Fable 5.1 is the stronger all-rounder.GLM-5.3-Flash is cheaper.
Scores updated · 39 tests both models report · How we compare
Where each one wins
Tests won in each of the eight areas we test. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- CodingWriting and fixing software50Claude Fable 5.15 of 5 tests
- ReasoningHard problems that need careful thinking50Claude Fable 5.15 of 5 tests
- MathCompetition and research-level math30Claude Fable 5.13 of 3 tests
- AgentsCarrying out multi-step tasks on its own21Claude Fable 5.12 of 4 tests · 1 tie
- FactsGetting facts right instead of making them up21Claude Fable 5.12 of 3 tests
- Images and chartsUnderstanding pictures, charts and video10Claude Fable 5.11 of 1 test
- Long documentsFinding answers in very long texts10Claude Fable 5.11 of 1 test
- Following instructionsDoing exactly what it is asked10Claude Fable 5.11 of 1 test
Images and charts, long documents and following instructions rest on a single test each.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
GLM-5.3-Flash costs 99% less for the same work.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Fable 5.1 pulls ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+70.7points ahead
- Answers hard knowledge questions correctlyAA-Omniscience · Accuracy+39.7points ahead
- Short factual questions, answered correctlySimpleQA Verified+38.8points ahead
Where GLM-5.3-Flash pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+45points ahead
- Finds the root cause of IT system incidentsAA IT-Bench SRE+1.7points ahead
Every test, side by side
All 39 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Fable 5.1
- LMArena · WebDevClaude Fable 5.1 by 133 rating points17421609+133 rating
- SciCodeClaude Fable 5.1 by 11.563.151.6+11.5
- LiveBench · Agentic CodingClaude Fable 5.1 by 9.366.156.8+9.3
- LiveBench · CodingClaude Fable 5.1 by 7.486.479+7.4
- Terminal-Bench 2.1Claude Fable 5.1 by 7.191.484.3+7.1
AgentsClaude Fable 5.1
- Terminal-Bench 4.0Claude Fable 5.1 by 19.25232.8+19.2
- GDPValClaude Fable 5.1 by 5.562.757.2+5.5
- AA IT-Bench SREGLM-5.3-Flash by 1.749.551.2+1.7
- τ-Bench V3 · Bankingtie47.247.2tie
ReasoningClaude Fable 5.1
- ARC-AGI-2Claude Fable 5.1 by 24.29065.8+24.2
- Humanity's Last ExamClaude Fable 5.1 by 19.259.139.9+19.2
- CritPtClaude Fable 5.1 by 14.329.715.4+14.3
- LiveBench · ReasoningClaude Fable 5.1 by 14.191.777.6+14.1
- GPQA DiamondClaude Fable 5.1 by 2.593.791.2+2.5
FactsClaude Fable 5.1
- AA-Omniscience · Non-hallucinationGLM-5.3-Flash by 4527.472.4+45
- AA-Omniscience · AccuracyClaude Fable 5.1 by 39.767.227.5+39.7
- SimpleQA VerifiedClaude Fable 5.1 by 38.870.832+38.8
Images and chartsClaude Fable 5.1
- LMArena · VisionClaude Fable 5.1 by 27 rating points13221295+27 rating
MathClaude Fable 5.1
- FrontierMath Tier 4Claude Fable 5.1 by 70.787.817.1+70.7
- FrontierMath Tiers 1-3 (v2)Claude Fable 5.1 by 34.490.255.8+34.4
- LiveBench · MathematicsClaude Fable 5.1 by 15.89781.2+15.8
Following instructionsClaude Fable 5.1
- LiveBench · Instruction FollowingClaude Fable 5.1 by 20.27352.8+20.2
Other results16 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- HLE-DiamondClaude Fable 5.1 by 41.960.118.2+41.9
- Terminal-Bench-Science 0.1Claude Fable 5.1 by 38.543.34.8+38.5
- AA-OmniscienceClaude Fable 5.1 by 3643.57.5+36
- CritPt v2 HardClaude Fable 5.1 by 2852.524.5+28
- Vals IndexClaude Fable 5.1 by 14.965.850.9+14.9
- livebench_languageClaude Fable 5.1 by 12.289.577.3+12.2
- AA IntelligenceClaude Fable 5.1 by 11.653.441.8+11.6
- GDP (Surge AI)Claude Fable 5.1 by 10.826.215.4+10.8
- Artificial Analysis Coding IndexClaude Fable 5.1 by 10.181.671.5+10.1
- GDPval-AA 2.1Claude Fable 5.1 by 86 rating points17351649+86 rating
- PostTrain Bench v1.2Claude Fable 5.1 by 7.844.636.8+7.8
- AA Agentic IndexClaude Fable 5.1 by 6.85851.2+6.8
- OfficeQA ProClaude Fable 5.1 by 6.66962.4+6.6
- ARC-AGI-1Claude Fable 5.1 by 6.597.591+6.5
- DeepSWE 1.1Claude Fable 5.1 by 467.463.4+4
- livebench_data_analysisClaude Fable 5.1 by 3.980.376.4+3.9
Questions people ask
Which is better, Claude Fable 5.1 or GLM-5.3-Flash?
Claude Fable 5.1 wins all eight areas we test: coding, agents, reasoning, facts, images and charts, math, long documents and following instructions. GLM-5.3-Flash wins none, but costs 99% less.
Which is better for coding?
Claude Fable 5.1. It wins 5 of the 5 coding tests both models report; GLM-5.3-Flash wins none.
Which is cheaper?
Claude Fable 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; GLM-5.3-Flash costs $0.15 and $0.50. That makes GLM-5.3-Flash about 99% cheaper for the same work.
How do you compare the two?
We use the 39 benchmark tests both models have published scores on. The verdict counts the 23 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 16 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.