GLM-5.3-Flash vs GPT OSS 120B
GLM-5.3-Flash significantly outperforms across most benchmarks. GPT OSS 120B is 1.3x cheaper per token.
Zhipu AI · OpenAI · Updated for 2026
Which is better?
GLM-5.3-Flash outperforms in 1 benchmarks (Humanity's Last Exam), while GPT OSS 120B is better at 0 benchmarks. GLM-5.3-Flash significantly outperforms across most benchmarks.
On price, GPT OSS 120B is roughly 1.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GLM-5.3-Flash also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current benchmark, pricing, and model metadata for 2026.
Choose GLM-5.3-Flash
- you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
- you process long inputs — it offers a 1,000,000 token context window
- you want the most recent training data — it shipped Aug 2026
Choose GPT OSS 120B
- cost matters — it's about 1.3x cheaper per token
At a glance
The differences that matter most.
Performance Benchmarks
Comparative analysis across standard metrics
GLM-5.3-Flash outperforms in 1 benchmarks (Humanity's Last Exam), while GPT OSS 120B is better at 0 benchmarks.
GLM-5.3-Flash significantly outperforms across most benchmarks.
Arena Performance
Playground indexes and blind preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GLM-5.3-Flash ($0.15/1M tokens) is 1.7x more expensive than GPT OSS 120B ($0.09/1M tokens).
For output processing, GLM-5.3-Flash ($0.50/1M tokens) is 1.1x more expensive than GPT OSS 120B ($0.45/1M tokens).
In conclusion, GLM-5.3-Flash is more expensive than GPT OSS 120B.*
* Using a 3:1 ratio of input to output tokens
Model Size
Parameter count comparison
GLM-5.3-Flash has 203.2B more parameters than GPT OSS 120B, making it 174.0% larger.
Context Window
Maximum input and output token capacity
GLM-5.3-Flash accepts 1,000,000 input tokens compared to GPT OSS 120B's 131,072 tokens. Both models can generate responses up to 131,072 tokens.
Input Capabilities
Supported data types and modalities
GLM-5.3-Flash supports multimodal inputs, whereas GPT OSS 120B does not.
GLM-5.3-Flash can handle both text and other forms of data like images, making it suitable for multimodal applications.
GLM-5.3-Flash
GPT OSS 120B
License
Usage and distribution terms
GLM-5.3-Flash is licensed under MIT, while GPT OSS 120B uses Apache 2.0.
License differences may affect how you can use these models in commercial or open-source projects.
MIT
Open weights
Apache 2.0
Open weights
Release Timeline
When each model was launched
GLM-5.3-Flash was released on 2026-08-26, while GPT OSS 120B was released on 2025-08-05.
GLM-5.3-Flash is 13 months newer than GPT OSS 120B.
Aug 26, 2026
0 days ago
1.1yr newerAug 5, 2025
1.1 years ago
Knowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
GLM-5.3-Flash is available from ZAI. GPT OSS 120B is available from DeepInfra, Novita, OpenAI, Fireworks, Groq.
GLM-5.3-Flash
GPT OSS 120B
Outputs Comparison
Judge for yourself.
Run your own prompts against GLM-5.3-Flash and GPT OSS 120B side-by-side, then vote on the output you prefer.
FAQ
Common questions about GLM-5.3-Flash vs GPT OSS 120B.