The Known Good Updated 8 Oct 2026 Subscribe
OpenAI: o3 vs Z.ai: GLM 5 ·OpenAI vs Z.ai

OpenAI: o3 vs Z.ai: GLM 5 — head-to-head comparison

OpenAI: o3 profile Z.ai: GLM 5 profile All comparisons
OpenAI: o3 — OpenAI
Quality
#26 of 65
72based on 5 of 7 evaluations
Known Good Index
Speed
#201 of 356
58.5
Output tokens per second
Price
#395 of 504
$3.50
Blended per 1M tokens
In $2.00 · Out $8.00
Cache hit price
#356 of 384
$0.50
per 1M tokens (−75%)
Context
#387 of 550
200k
tokens (~300 pages)
Z.ai: GLM 5 — Z.ai
Quality
#20 of 65
77based on 4 of 7 evaluations
Known Good Index
Speed
#205 of 356
57.1
Output tokens per second
Price
#260 of 504
$0.93
Blended per 1M tokens
In $0.60 · Out $1.92
Cache hit price
#223 of 384
$0.12
per 1M tokens (−80%)
Context
#357 of 550
205k
tokens (~300 pages)
Summary

On the Known Good Index, OpenAI: o3 scores 72 and Z.ai: GLM 5 scores 77 — a 5-point lead for Z.ai: GLM 5. They share 3 published evaluations, with OpenAI: o3 ahead on 1 and Z.ai: GLM 5 ahead on 2.

Blended pricing is $3.50 per 1M tokens for OpenAI: o3 and $0.93 for Z.ai: GLM 5 — Z.ai: GLM 5 is about 3.8× cheaper.

Throughput is 58 tokens per second for OpenAI: o3 and 57 for Z.ai: GLM 5, with time to first token at 3.0s and 2.6s. OpenAI: o3 accepts 200k tokens of context against 205k.

OpenAI: o3 is proprietary; Z.ai: GLM 5 is open weights under Open weights (unrestricted). 15 tracked hosts serve one or both.

Generated from tracked data on 8 Oct 2026 · how these comparisons are computed →

At a glance
MetricOpenAI: o3Z.ai: GLM 5
Known Good Index 72 based on 5 of 7 evaluations 77 based on 4 of 7 evaluations
Blended $/1M $3.50 $0.93
Output tok/s 58 57
Context window 200k 205k
Providers 1 14
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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
Known Good Index 72 77
Coding Index — 69
Mathematics Index 92 —
Reasoning Index 59 —
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 · scores ingested from Epoch AI (CC-BY 4.0)

GPQA Diamond82 / 88
Mock AIME 2024–2584 / 80
SWE-bench Verified62 / 72

Right-hand figures read OpenAI: o3 / Z.ai: GLM 5. OpenAI: o3 leads on 1 of 3, Z.ai: GLM 5 on 2.

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
Text Arena — 1,446
Text Arena (style controlled) — 1,458
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
Input $/1M $2.00 $0.60
Output $/1M $8.00 $1.92
Blended $/1M $3.50 $0.93
Cache read $/1M $0.500 $0.120
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
Context window 200k 205k
Max output tokens 100k 128k
The Known Good

Speed & Latency

Mean throughput and time to first token across hosting providers, over successful measurements from the last 48 hours

Throughput and latency

Means across all tracked providers over successful measurements from the last 48 hours, derived from OpenRouter endpoint telemetry.

MetricOpenAI: o3Z.ai: GLM 5
Output tokens/s 58 57
Time to first token 3.0s 2.6s
The Known Good

Providers

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

15 hosts
Full provider benchmarks →
Provider OpenAI: o3 blendedOpenAI: o3 tok/s Z.ai: GLM 5 blendedZ.ai: GLM 5 tok/s
OpenAI · first party $3.50 44 — —
Amazon Bedrock · first party — — $1.55 111
Baidu · first party — — $1.08 65
Venice — — $1.55 65
Z.AI · first party — — $1.55 48
Chutes — — $1.35 45
GMICloud — — $0.93 43
Novita — — $1.55 41
StreamLake — — $0.93 39
SiliconFlow — — $1.35 36
AtlasCloud — — $1.50 35
DeepInfra — — $0.97 16
DigitalOcean — — $1.55 7
Parasail — — $1.55 —
Phala — — $1.77 —

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 →