The Known Good Updated 29 Jul 2026
OpenAI: gpt-oss-120b vs Z.ai: GLM 5.2 ·OpenAI vs Z.ai

OpenAI: gpt-oss-120b vs Z.ai: GLM 5.2 — head-to-head comparison

OpenAI: gpt-oss-120b profile Z.ai: GLM 5.2 profile All comparisons
OpenAI: gpt-oss-120b — OpenAI
Quality
#42 of 62
61based on 3 of 7 evaluations
Known Good Index
Speed
#13 of 317
144.7
Output tokens per second
Price
#35 of 370
$0.07
Blended per 1M tokens
In $0.04 · Out $0.17
Cache hit price
#28 of 238
$0.015
per 1M tokens (−59%)
Context
#265 of 375
131k
tokens (~200 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: gpt-oss-120b scores 61 and Z.ai: GLM 5.2 scores 91 — a 30-point lead for Z.ai: GLM 5.2. They share 2 published evaluations, with OpenAI: gpt-oss-120b ahead on 1 and Z.ai: GLM 5.2 ahead on 1.

Blended pricing is $0.07 per 1M tokens for OpenAI: gpt-oss-120b and $1.16 for Z.ai: GLM 5.2 — OpenAI: gpt-oss-120b is about 16.6× cheaper.

Throughput is 145 tokens per second for OpenAI: gpt-oss-120b and 48 for Z.ai: GLM 5.2, with time to first token at 0.9s and 2.2s. OpenAI: gpt-oss-120b accepts 131k tokens of context against 1.05M.

OpenAI: gpt-oss-120b is open weights under Open weights (unrestricted); Z.ai: GLM 5.2 is open weights under Open weights (unrestricted). 37 tracked hosts serve one or both, and 9 serve both.

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

At a glance
MetricOpenAI: gpt-oss-120bZ.ai: GLM 5.2
Known Good Index 61 based on 3 of 7 evaluations 91 based on 3 of 7 evaluations
Blended $/1M $0.07 $1.16
Output tok/s 145 48
Context window 131k 1.05M
Providers 17 29
Jump to section

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: gpt-oss-120bZ.ai: GLM 5.2
Known Good Index 61 91
Mathematics Index 89 86
Agentic Index 18 91
Openness Index 60 60
The Known Good

Quality Breakdown

Every evaluation both models report a published score for

Evaluations both models report

Bar = OpenAI: gpt-oss-120b · marker = Z.ai: GLM 5.2 · scores ingested from Epoch AI (CC-BY 4.0)

GPQA Diamond76 / 92
Mock AIME 2024–2589 / 86

Right-hand figures read OpenAI: gpt-oss-120b / Z.ai: GLM 5.2. OpenAI: gpt-oss-120b leads on 1 of 2, Z.ai: GLM 5.2 on 1.

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: gpt-oss-120bZ.ai: GLM 5.2
Text Arena 1,366 1,464
Text Arena (style controlled) 1,352 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: gpt-oss-120bZ.ai: GLM 5.2
Input $/1M $0.04 $0.76
Output $/1M $0.17 $2.38
Blended $/1M $0.07 $1.16
Cache read $/1M $0.015 $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: gpt-oss-120bZ.ai: GLM 5.2
Context window 131k 1.05M
Max output tokens 131k 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: gpt-oss-120bZ.ai: GLM 5.2
Output tokens/s 145 48
Time to first token 0.9s 2.2s
The Known Good

Providers

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

37 hosts · 9 serve both
Full provider benchmarks →
Provider OpenAI: gpt-oss-120b blendedOpenAI: gpt-oss-120b tok/s Z.ai: GLM 5.2 blendedZ.ai: GLM 5.2 tok/s
Cerebras $0.45 501
SambaNova $0.34 367
Groq $0.26 352
Amazon Bedrock · first party $0.26 342
Nebius $0.26 231
DeepInfra $0.07 196 $1.45 56
Google · first party $0.16 177
BaseTen $0.20 171 $2.15 150
Mara $0.30 146
Together $0.26 114 $2.15 98
Parasail $0.26 101 $2.15 65
Phala $0.26 82 $2.15 50
Novita $0.10 64 $1.16 27
Mancer 2 $0.17 40
CoreWeave $0.07 32 $1.18 67
DigitalOcean $0.17 22 $1.89 26
SiliconFlow $0.15 12 $2.00 31
Friendli $2.15 101
Wafer $1.94 91
Ionstream $2.15 83
Fireworks $2.15 80
Decart $1.52 77
Chutes $1.93 68
Alibaba · first party $1.24 65
Io Net $4.32 54
Morph $1.85 54
Baidu · first party $1.07 53
Cloudflare $2.15 53
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
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 →