The Known Good Updated 29 Jul 2026
OpenAI: o3 vs Z.ai: GLM 5.2 ·OpenAI vs Z.ai

OpenAI: o3 vs Z.ai: GLM 5.2 — head-to-head comparison

OpenAI: o3 profile Z.ai: GLM 5.2 profile All comparisons
OpenAI: o3 — OpenAI
Quality
#25 of 62
74based on 5 of 7 evaluations
Known Good Index
Speed
#85 of 317
70.8
Output tokens per second
Price
#292 of 370
$3.50
Blended per 1M tokens
In $2.00 · Out $8.00
Cache hit price
#204 of 238
$0.50
per 1M tokens (−75%)
Context
#226 of 375
200k
tokens (~300 pages)
Z.ai: GLM 5.2 — Z.ai
Quality
#8 of 62
91based on 3 of 7 evaluations
Known Good Index
Speed
#164 of 317
47.5
Output tokens per second
Price
#224 of 370
$1.16
Blended per 1M tokens
In $0.76 · Out $2.38
Cache hit price
#142 of 238
$0.14
per 1M tokens (−81%)
Context
#57 of 375
1.05M
tokens (~1,600 pages)
Summary

On the Known Good Index, OpenAI: o3 scores 74 and Z.ai: GLM 5.2 scores 91 — a 18-point lead for Z.ai: GLM 5.2. They share 3 published evaluations, with OpenAI: o3 ahead on 0 and Z.ai: GLM 5.2 ahead on 3.

Blended pricing is $3.50 per 1M tokens for OpenAI: o3 and $1.16 for Z.ai: GLM 5.2 — Z.ai: GLM 5.2 is about 3.0× cheaper.

Throughput is 71 tokens per second for OpenAI: o3 and 48 for Z.ai: GLM 5.2, with time to first token at 3.6s and 2.2s. OpenAI: o3 accepts 200k tokens of context against 1.05M.

OpenAI: o3 is proprietary; Z.ai: GLM 5.2 is open weights under Open weights (unrestricted). 30 tracked hosts serve one or both.

Generated from tracked data on 29 Jul 2026 · how these comparisons are computed →

At a glance
MetricOpenAI: o3Z.ai: GLM 5.2
Known Good Index 74 based on 5 of 7 evaluations 91 based on 3 of 7 evaluations
Blended $/1M $3.50 $1.16
Output tok/s 71 48
Context window 200k 1.05M
Providers 1 29
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Quality

Known Good Index and the capability indices, side by side

Index scores

Each index is min-max normalised across tracked models and scaled 0–100 from published evaluations. We do not run these evaluations.

MetricOpenAI: o3Z.ai: GLM 5.2
Known Good Index 74 91
Mathematics Index 92 86
Reasoning Index 62
Agentic Index 60 91
Openness Index 5 60
The Known Good

Quality Breakdown

Every evaluation both models report a published score for

Evaluations both models report

Bar = OpenAI: o3 · marker = Z.ai: GLM 5.2 · scores ingested from Epoch AI (CC-BY 4.0)

GPQA Diamond82 / 92
Mock AIME 2024–2584 / 86
SWE-bench Verified62 / 79

Right-hand figures read OpenAI: o3 / Z.ai: GLM 5.2. OpenAI: o3 leads on 0 of 3, Z.ai: GLM 5.2 on 3.

The Known Good

Arena Elo

Human preference rating from blind pairwise votes

Arena ratings

Elo from blind pairwise votes, ingested from Arena. Higher is better.

MetricOpenAI: o3Z.ai: GLM 5.2
Text Arena 1,464
Text Arena (style controlled) 1,469
The Known Good

Price & Cost

Published API pricing by token type

Published pricing

USD per 1M tokens. Blended is a 3:1 input:output mix. Live from OpenRouter, cross-checked against models.dev. Lower is better.

MetricOpenAI: o3Z.ai: GLM 5.2
Input $/1M $2.00 $0.76
Output $/1M $8.00 $2.38
Blended $/1M $3.50 $1.16
Cache read $/1M $0.500 $0.141
The Known Good
We publish blended price rather than cost-per-task. Cost-per-task requires token counts from an evaluation suite we do not run. Blended price is computed from published rates and is fully reproducible — see the pricing methodology.

Context Window

Maximum input accepted and maximum output emitted

Context and output limits

Provider-declared limits, from metadata via models.dev and OpenRouter. Higher is better.

MetricOpenAI: o3Z.ai: GLM 5.2
Context window 200k 1.05M
Max output tokens 100k 131k
The Known Good

Speed & Latency

Median throughput and time to first token across hosting providers

Output speedTime to first token
Throughput and latency

Medians across all tracked providers, derived from OpenRouter endpoint telemetry.

MetricOpenAI: o3Z.ai: GLM 5.2
Output tokens/s 71 48
Time to first token 3.6s 2.2s
The Known Good

Providers

Which hosts serve each model, and at what price and speed

30 hosts
Full provider benchmarks →
Provider OpenAI: o3 blendedOpenAI: o3 tok/s Z.ai: GLM 5.2 blendedZ.ai: GLM 5.2 tok/s
OpenAI · first party $3.50 84
BaseTen $2.15 150
Friendli $2.15 101
Together $2.15 98
Wafer $1.94 91
Ionstream $2.15 83
Fireworks $2.15 80
Decart $1.52 77
Chutes $1.93 68
CoreWeave $1.18 67
Alibaba · first party $1.24 65
Parasail $2.15 65
DeepInfra $1.45 56
Io Net $4.32 54
Morph $1.85 54
Baidu · first party $1.07 53
Cloudflare $2.15 53
Phala $2.15 50
Sail Research $1.62 47
AkashML $1.18 44
Ambient $1.89 44
GMICloud $1.42 37
AtlasCloud $1.94 35
Venice $2.15 35
Z.AI · first party $2.15 32
SiliconFlow $2.00 31
Novita $1.16 27
DigitalOcean $1.89 26
StreamLake $1.16 26
Inceptron $1.43 8

Per-host pricing and telemetry from OpenRouter. A dash means that host does not serve that model.

The Known Good
Sources for this page
Pricing & providers — OpenRouter Metadata — models.dev Benchmarks — Epoch AI (CC-BY 4.0)Elo — Arena Full attribution →