GLM 5.2 on Fireworks Makes Opus 4.8 and GPT 5.5 Feel Slow

Melvin Vivas · X post · 2026-06-27 · Open on X

Topics: LLM Fundamentals, LLMOps, Deployment & Monitoring · Level: beginner

Summary

The creator compared GLM 5.2 served by Fireworks AI with Opus 4.8 and GPT 5.5 and found GLM 5.2 far faster. The takeaway is that inference speed, which depends on both model and provider, is a key factor when choosing a model.

Key points

• GLM 5.2 on Fireworks AI was much faster than Opus 4.8 and GPT 5.5 in the creator's comparison.
• Fast inference providers can make open models feel far more responsive than frontier APIs.
• Weigh speed against quality when picking a model for interactive work.

Resources mentioned

• Fireworks AI · tool · x.com · free
  Fireworks AI's official X account, which posts news about inference and serving open models.
  Also in: FireRouter: cost-aware model routing between open models and Claude Opus (Melvin Vivas on X · notes), GLM 5.2 Hits 446 tok/s on Fireworks AI (Melvin Vivas on X · notes), GLM 5.2 Speed vs Opus 4.8 and GPT 5.5 (Melvin Vivas on X · notes), Fastest GLM-5.2 Provider: Fireworks AI at 343 tok/s (Melvin Vivas on X · notes) and 4 more
• GLM 5.2 · tool · huggingface.co · free
  A GLM-family LLM (the transcript says 'GLM-5-2') that the demo ranked as a strong, affordable model for coding and design.
  Also in: Qwen3.8-Max on the Frontend Code Arena cost-performance frontier (Melvin Vivas on X · notes), Models That Work With the Hermes Agent for Personal Productivity (Melvin Vivas on X · notes), Open Model GLM 5.2 Helped Mitigate OpenAI-Caused Cyberattack (Melvin Vivas on X · notes), AI News Roundup: Claude Fable 5, Scientist AI, ZCode, NVIDIA RL (Melvin Vivas on X · notes) and 27 more

Try this

• Try GLM 5.2 through Fireworks AI and compare its speed with your current model.