Top Open Source LLMs
October 2025 Complete Guide

Published: October 1, 202518 min readBy Dylan

The open source AI landscape has reached unprecedented heights in 2025. From DeepSeek's V3.1 Terminus with its 671B parameters to Alibaba's Qwen3-235B dominating mathematical reasoning, we analyze the top performers, their benchmarks, pricing, and practical applications in this comprehensive guide.

Executive Summary

🏆 Top Performers

DeepSeek V3.1 Terminus:58/70
GPT-OSS-120B:58/70
DeepSeek V3.2 Exp:57/70
Qwen3-235B A22B:57/70

🚀 Key Trends

  • MoE Dominance: All top models use Mixture of Experts
  • Massive Scale: 120B-671B parameter ranges
  • Reasoning Focus: Enhanced mathematical & coding abilities
  • Cost Efficiency: Competitive pricing vs proprietary models
  • Long Context: 128K-256K token windows

📊 Market Overview

October 2025 marks a watershed moment for open source AI. Chinese companies (DeepSeek, Alibaba) lead in raw performance, while Western models focus on efficiency and reasoning. The gap between open source and proprietary models has narrowed dramatically, with several open source models now matching or exceeding commercial offerings in specific domains.

Model Rankings & Performance

Quality Index Leaderboard

RankModelQuality IndexParametersContext
#1DeepSeek V3.1 Terminus58/70671B128K
#2GPT-OSS-120B58/70120B128K
#3DeepSeek V3.2 Exp57/70671B128K
#4Qwen3-235B A22B 250757/70235B256K
#5GLM-4.656/70355B131K
#6Qwen3 Max55/70235B256K

📈 Performance Analysis

The top tier (58/70) is dominated by DeepSeek V3.1 Terminus and GPT-OSS-120B, both achieving exceptional performance across diverse benchmarks. The second tier (57/70) shows remarkable consistency with DeepSeek V3.2 Exp and Qwen3-235B A22B 2507, demonstrating the maturity of current MoE architectures. Notably, parameter count doesn't directly correlate with performance, as GPT-OSS-120B matches DeepSeek V3.1's 671B parameters with superior efficiency.

Detailed Model Analysis

🥇 DeepSeek V3.1 Terminus

Specifications

  • Parameters: 671B total (MoE architecture)
  • Context: 128K tokens
  • Architecture: Mixture of Experts
  • Release: August 2025
  • License: Apache 2.0

Key Benchmarks

  • GPQA Diamond: 80.1%
  • MMLU: ~88-90
  • AIME25: ~75-80
  • LiveCodeBench: ~60-65
  • Tool Use: Excellent

Analysis: DeepSeek V3.1 Terminus represents the pinnacle of open source AI as of October 2025. Its 671B parameter MoE architecture delivers exceptional performance across reasoning, coding, and general knowledge tasks. The model excels in graduate-level reasoning (GPQA Diamond: 80.1%) and maintains strong performance in mathematical and coding benchmarks. Its Apache 2.0 license makes it fully commercial-ready.

🥈 GPT-OSS-120B

Specifications

  • Parameters: 120B (dense architecture)
  • Context: 128K tokens
  • Architecture: Dense Transformer
  • Release: September 2025
  • License: MIT

Key Benchmarks

  • MMLU: ~89-91
  • AIME25: ~78-82
  • LiveCodeBench: ~62-68
  • GPQA: ~78-82
  • Efficiency: Outstanding

Analysis: GPT-OSS-120B achieves remarkable efficiency with its 120B dense architecture, matching the performance of much larger MoE models. This represents a breakthrough in parameter efficiency, delivering top-tier performance with significantly lower computational requirements. The model excels in mathematical reasoning and coding tasks while maintaining excellent general knowledge capabilities.

🥉 DeepSeek V3.2 Exp

Specifications

  • Parameters: 671B (experimental)
  • Context: 128K tokens
  • Architecture: MoE + Sparse Attention
  • Release: September 2025
  • License: Apache 2.0

Key Features

  • Sparse Attention: Reduced computational costs
  • Long Context: Enhanced 128K handling
  • Pricing: 50%+ cost reduction
  • Performance: Matches V3.1 quality
  • Efficiency: Optimized inference

Analysis: DeepSeek V3.2 Exp introduces groundbreaking Sparse Attention mechanisms, reducing computational costs while maintaining performance parity with V3.1. This experimental model represents DeepSeek's next-generation architecture, offering 50%+ cost reductions and enhanced long-context processing capabilities. It's positioned as a bridge to their upcoming flagship model.

🏅 Qwen3-235B A22B 2507

Specifications

  • Parameters: 235B (22B active)
  • Context: 256K tokens
  • Architecture: MoE (128 experts)
  • Release: July 2025
  • License: Apache 2.0

Key Benchmarks

  • AIME25: 70.3
  • MultiPL-E: 87.9
  • MMLU: ~85-88
  • LiveCodeBench: ~55-60
  • Long Context: Excellent

Analysis: Qwen3-235B A22B 2507 excels in mathematical reasoning (AIME25: 70.3) and coding tasks (MultiPL-E: 87.9), outperforming many proprietary models. Its 256K context window makes it ideal for long-document processing and extended conversations. The model's FP8 optimization enables efficient inference while maintaining high quality across diverse tasks.

🏅 GLM-4.6

Specifications

  • Parameters: 355B (32B active)
  • Context: 131K tokens
  • Architecture: MoE
  • Release: August 2025
  • License: MIT

Key Features

  • Hybrid Reasoning: Thinking/Non-thinking modes
  • Tool Use: 90.6% success rate
  • Multi-modal: Text + structured output
  • Agentic: Excellent for AI agents
  • Stability: Consistent performance

Analysis: GLM-4.6 continues Z.ai's tradition of hybrid reasoning capabilities, offering both thinking and non-thinking modes for different use cases. Its 90.6% tool use success rate makes it ideal for production AI agents. The model excels in multi-modal tasks and structured output generation, making it perfect for enterprise applications requiring reliable, consistent performance.

🏅 Qwen3 Max

Specifications

  • Parameters: 235B (optimized)
  • Context: 256K tokens
  • Architecture: MoE (enhanced)
  • Release: September 2025
  • License: Apache 2.0

Key Features

  • Enhanced Reasoning: Improved logic
  • Long Context: 256K optimization
  • Multi-language: Strong multilingual
  • Efficiency: Optimized inference
  • Versatility: Broad task coverage

Analysis: Qwen3 Max represents Alibaba's optimization of their flagship model, delivering enhanced reasoning capabilities and improved efficiency. While scoring slightly lower than the A22B variant, it offers better versatility across diverse tasks and improved multilingual capabilities. The model excels in long-context scenarios and provides excellent value for applications requiring broad task coverage.

Benchmark Deep Dive

Mathematical Reasoning

ModelAIME25MATH 500GPQA DiamondRank
DeepSeek V3.1 Terminus~78-82~95-9880.1🥇
GPT-OSS-120B~78-82~95-98~78-82🥈
DeepSeek V3.2 Exp~75-80~92-96~78-82🥉
Qwen3-235B A22B 250770.3~88-92~75-804th

Coding & Programming

ModelLiveCodeBenchMultiPL-ESWE-benchRank
GPT-OSS-120B~62-68~85-90~65-70🥇
Qwen3-235B A22B 2507~55-6087.9~60-65🥈
DeepSeek V3.1 Terminus~60-65~82-87~62-68🥉
GLM-4.6~45-50~78-83~58-634th

📊 Benchmark Insights

Mathematical reasoning shows DeepSeek V3.1 Terminus leading in graduate-level reasoning (GPQA Diamond: 80.1%), while GPT-OSS-120B excels in coding tasks with superior efficiency. Qwen3-235B A22B 2507 demonstrates strong mathematical capabilities (AIME25: 70.3) and coding performance (MultiPL-E: 87.9). The benchmarks reveal that different models excel in different domains, with no single model dominating all areas.

Pricing & Cost Analysis

Provider Pricing Comparison

Most Affordable

Qwen3-235B (Deepinfra)$0.25/M
Input: $0.13/M • Output: $0.60/M
DeepSeek V3.2 Exp (Deepinfra)$0.35/M
Input: $0.20/M • Output: $0.80/M
GLM-4.6 (SiliconFlow)$0.88/M
Input: $0.50/M • Output: $2.00/M

Premium Performance

DeepSeek V3.1 Terminus (Deepinfra)$0.45/M
Input: $0.25/M • Output: $1.00/M
GPT-OSS-120B (Together)$0.60/M
Input: $0.35/M • Output: $1.20/M
Qwen3 Max (Fireworks)$0.75/M
Input: $0.40/M • Output: $1.50/M

💰 Cost Efficiency Analysis

75%
Cost savings vs GPT-4o
$0.25
Best price per M tokens
3.2x
Better value vs proprietary
58/70
Quality at lowest cost

Open source models deliver exceptional value, with Qwen3-235B offering 75% cost savings compared to proprietary alternatives while maintaining competitive performance. The pricing landscape shows clear tiers: budget options under $0.50/M tokens, mid-tier around $0.60-0.75/M, and premium models at $0.88/M+.

Use Cases & Recommendations

🎯 Research & Development

DeepSeek V3.1 Terminus

Best for cutting-edge research requiring maximum performance and graduate-level reasoning capabilities.

GPT-OSS-120B

Ideal for research teams needing efficient performance with lower computational requirements.

DeepSeek V3.2 Exp

Perfect for experimental projects leveraging next-generation sparse attention mechanisms.

🎯 Production Applications

Qwen3-235B A22B 2507

Excellent for cost-sensitive production apps requiring strong mathematical and coding capabilities.

GLM-4.6

Best for enterprise applications needing reliable tool use and hybrid reasoning modes.

Qwen3 Max

Ideal for multilingual applications and long-context processing requirements.

💻 Coding & Development

Best: GPT-OSS-120B, Qwen3-235B A22B 2507
Use Cases: Code generation, debugging, software development
Key Features: MultiPL-E 87.9, LiveCodeBench excellence

🧮 Mathematical Reasoning

Best: DeepSeek V3.1 Terminus, GPT-OSS-120B
Use Cases: Scientific computing, research, education
Key Features: GPQA Diamond 80.1%, AIME25 excellence

🤖 AI Agents & Automation

Best: GLM-4.6, DeepSeek V3.1 Terminus
Use Cases: Autonomous agents, tool use, automation
Key Features: 90.6% tool success, hybrid reasoning

🏆 Final Recommendations

🥇

Overall Best

DeepSeek V3.1 Terminus

Maximum performance across all domains

💰

Best Value

Qwen3-235B A22B 2507

$0.25/M tokens + strong performance

Most Efficient

GPT-OSS-120B

120B params matching 671B performance

Future Outlook & Trends

The open source AI landscape in October 2025 represents a mature ecosystem where performance gaps with proprietary models have largely closed, while cost advantages remain substantial.

🔮 Emerging Trends

  • Sparse Attention: DeepSeek V3.2 Exp pioneering cost reduction
  • Parameter Efficiency: GPT-OSS-120B showing 120B can match 671B
  • Long Context: 256K+ becoming standard
  • Reasoning Modes: Hybrid thinking/non-thinking architectures
  • Tool Integration: Native agentic capabilities

📈 Market Dynamics

  • Chinese Leadership: DeepSeek and Alibaba leading innovation
  • Cost Competition: Aggressive pricing driving adoption
  • Open Source Advantage: 75%+ cost savings vs proprietary
  • Performance Parity: Quality gaps narrowing rapidly
  • Enterprise Adoption: Production deployments increasing

Looking Ahead: The next 6-12 months will likely see continued innovation in sparse attention mechanisms, further parameter efficiency improvements, and enhanced reasoning capabilities. Chinese companies appear positioned to maintain their leadership in raw performance, while Western models focus on efficiency and specialized applications.

Key Takeaways for Developers

For New Projects:

  • ✅ Start with Qwen3-235B for cost efficiency
  • ✅ Upgrade to DeepSeek V3.1 for maximum performance
  • ✅ Consider GPT-OSS-120B for balanced efficiency
  • ✅ Use GLM-4.6 for agentic applications

For Production:

  • ✅ Monitor DeepSeek V3.2 Exp for cost reductions
  • ✅ Evaluate long-context models for document processing
  • ✅ Consider hybrid reasoning for complex tasks
  • ✅ Plan for 256K+ context requirements

The open source AI revolution has reached a critical inflection point. With models now matching proprietary performance at a fraction of the cost, the barriers to AI adoption have dramatically lowered. Organizations that embrace these models today will have significant competitive advantages in the coming years, while those waiting for "perfect" solutions may find themselves left behind in an increasingly AI-driven world.

Related Resources

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