Quality
Known Good Index and the capability indices, side by side
Each index is min-max normalised across tracked models and scaled 0–100 from published evaluations. We do not run these evaluations.
| Metric | OpenAI: GPT-5 | Z.ai: GLM 5.1 |
|---|---|---|
| Known Good Index | 78 | 88 |
| Coding Index | 67 | — |
| Mathematics Index | 96 | 92 |
| Reasoning Index | 71 | — |
| Agentic Index | 67 | 82 |
| Openness Index | 5 | 5 |
Quality Breakdown
Every evaluation both models report a published score for
Bar = OpenAI: GPT-5 · marker = Z.ai: GLM 5.1 · scores ingested from Epoch AI (CC-BY 4.0)
Right-hand figures read OpenAI: GPT-5 / Z.ai: GLM 5.1. OpenAI: GPT-5 leads on 1 of 3, Z.ai: GLM 5.1 on 2.
Arena Elo
Human preference rating from blind pairwise votes
Elo from blind pairwise votes, ingested from Arena. Higher is better.
| Metric | OpenAI: GPT-5 | Z.ai: GLM 5.1 |
|---|---|---|
| Text Arena | — | 1,465 |
| Text Arena (style controlled) | — | 1,469 |
Price & Cost
Published API pricing by token type
USD per 1M tokens. Blended is a 3:1 input:output mix. Live from OpenRouter, cross-checked against models.dev. Lower is better.
| Metric | OpenAI: GPT-5 | Z.ai: GLM 5.1 |
|---|---|---|
| Input $/1M | $1.25 | $0.97 |
| Output $/1M | $10.00 | $3.04 |
| Blended $/1M | $3.44 | $1.48 |
| Cache read $/1M | $0.125 | $0.179 |
Context Window
Maximum input accepted and maximum output emitted
Provider-declared limits, from metadata via models.dev and OpenRouter. Higher is better.
| Metric | OpenAI: GPT-5 | Z.ai: GLM 5.1 |
|---|---|---|
| Context window | 400k | 205k |
| Max output tokens | 128k | 128k |
Speed & Latency
Median throughput and time to first token across hosting providers
Medians across all tracked providers, derived from OpenRouter endpoint telemetry.
| Metric | OpenAI: GPT-5 | Z.ai: GLM 5.1 |
|---|---|---|
| Output tokens/s | 48 | 53 |
| Time to first token | 2.1s | 1.8s |
Providers
Which hosts serve each model, and at what price and speed
| Provider | OpenAI: GPT-5 blended | OpenAI: GPT-5 tok/s | Z.ai: GLM 5.1 blended | Z.ai: GLM 5.1 tok/s |
|---|---|---|---|---|
| OpenAI · first party | $3.44 | 67 | — | — |
| Azure · first party | $3.44 | 46 | — | — |
| CoreWeave | — | — | $2.15 | 146 |
| Wafer | — | — | $1.55 | 87 |
| GMICloud | — | — | $1.50 | 66 |
| Parasail | — | — | $2.15 | 66 |
| Venice | — | — | $2.37 | 64 |
| DeepInfra | — | — | $1.66 | 62 |
| Friendli | — | — | $2.15 | 59 |
| SiliconFlow | — | — | $1.83 | 57 |
| Crusoe | — | — | $2.00 | 54 |
| Novita | — | — | $2.13 | 51 |
| StreamLake | — | — | $1.48 | 43 |
| Baidu · first party | — | — | $1.46 | 42 |
| Phala | — | — | $1.96 | 42 |
| Z.AI · first party | — | — | $2.15 | 42 |
| Chutes | — | — | $1.50 | 41 |
| Nebius | — | — | $2.15 | 29 |
| AtlasCloud | — | — | $1.94 | 27 |
| DigitalOcean | — | — | $1.81 | 20 |
| Fireworks | — | — | $2.15 | — |
Per-host pricing and telemetry from OpenRouter. A dash means that host does not serve that model.