The Known Good Updated 25 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
#33 of 61
61based on 3 of 6 evaluations
Known Good Index
Speed
#9 of 316
172.8
Output tokens per second
Price
#33 of 340
$0.07
Blended per 1M tokens
In $0.04 · Out $0.17
Cache hit price
#25 of 206
$0.015
per 1M tokens (−59%)
Context
#238 of 345
131k
tokens (~200 pages)
Z.ai: GLM 5.2 — Z.ai
Quality
#8 of 61
91based on 3 of 6 evaluations
Known Good Index
Speed
#147 of 316
55.2
Output tokens per second
Price
#204 of 340
$1.12
Blended per 1M tokens
In $0.73 · Out $2.28
Cache hit price
#116 of 206
$0.13
per 1M tokens (−81%)
Context
#45 of 345
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 $1.12 for Z.ai: GLM 5.2 — OpenAI: gpt-oss-120b is about 15.9× cheaper.

Throughput is 173 tokens per second for OpenAI: gpt-oss-120b and 55 for Z.ai: GLM 5.2, with time to first token at 0.7s and 1.7s. 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 26 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 6 evaluations 91 based on 3 of 6 evaluations
Blended $/1M $0.07 $1.12
Output tok/s 173 55
Context window 131k 1.05M
Providers 17 29
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Quality

Known Good Index and the capability indices, side by side

IndicesComponents
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
Science Index 77 97
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
MATH / AIME89 / 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

Per token typeCache discount
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 $0.73
Output $/1M $0.17 $2.28
Blended $/1M $0.07 $1.12
Cache read $/1M $0.015 $0.135
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 173 55
Time to first token 0.7s 1.7s
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 $0.45 505
Groq $0.26 445
SambaNova $0.34 304
DeepInfra $0.07 282 $1.45 49
BaseTen $0.20 255 $2.15 119
Nebius $0.26 255
Mara $0.30 198
Parasail $0.26 198 $2.15 56
Google · first party $0.16 197
Together $0.26 108 $2.15 47
Amazon Bedrock · first party $0.26 103
Phala $0.26 86 $2.15 46
Novita $0.10 67 $1.12 37
DigitalOcean $0.17 63 $1.89 13
Mancer 2 $0.17 49
SiliconFlow $0.15 29 $2.00 48
CoreWeave $0.07 24 $1.18 181
Wafer $2.15 103
Ionstream $2.15 101
Friendli $2.15 80
Cloudflare $2.15 74
Alibaba · first party $1.27 69
Fireworks $2.15 65
Decart $1.52 60
Chutes $1.93 56
Z.AI · first party $2.15 49
AkashML $1.18 46
Morph $1.85 43
Baidu · first party $1.12 40
GMICloud $1.42 39
Venice $2.15 39
AtlasCloud $1.94 38
StreamLake $1.11 37
Inceptron $1.43 29
Io Net $4.40 29
Sail Research $1.72 20
Ambient $1.89 14

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 →