Comprehensive side-by-side LLM comparison
GPT OSS 20B leads with 28.1% higher average benchmark score. GPT OSS 20B offers 241.7K more tokens in context window than GPT-3.5 Turbo. GPT OSS 20B is $1.75 cheaper per million tokens. GPT OSS 20B is available on 4 providers. Overall, GPT OSS 20B is the stronger choice for coding tasks.
OpenAI
GPT-OSS 20B was created as a smaller open-source variant, designed to balance capability with accessibility for researchers and developers. Built with 20 billion parameters, it provides a more approachable entry point for those seeking to work with open-source language models while benefiting from OpenAI's architectural insights.
OpenAI
GPT-3.5 Turbo was developed as an optimized version of GPT-3.5, designed to provide a balance of capability and efficiency for conversational and completion tasks. Built to serve as a cost-effective option for applications requiring reliable language understanding and generation, it became widely adopted for chatbots, content generation, and general-purpose AI assistance.
2 years newer

GPT-3.5 Turbo
OpenAI
2023-03-21

GPT OSS 20B
OpenAI
2025-08-05
Cost per million tokens (USD)

GPT OSS 20B

GPT-3.5 Turbo
Context window and performance specifications
Average performance across 2 common benchmarks

GPT OSS 20B

GPT-3.5 Turbo
GPT-3.5 Turbo
2021-09-30
Available providers and their performance metrics

GPT OSS 20B
Groq
Novita
OpenAI
ZeroEval

GPT OSS 20B

GPT-3.5 Turbo

GPT OSS 20B

GPT-3.5 Turbo

GPT-3.5 Turbo
Azure
OpenAI