OpenAI GPT-5.5 Powers Codex Coding Agent on NVIDIA GB200 Infrastructure

OpenAI has released GPT-5.5, its latest frontier model, according to NVIDIA. The model powers Codex, OpenAI's agentic coding application, running on NVIDIA GB200 NVL72 rack-scale systems.

The announcement comes via NVIDIA's official blog, which states that over 10,000 users are accessing the GPT-5.5-powered Codex. This marks the first confirmed deployment of GPT-5.5 in a production environment.

Deployment Details

GPT-5.5 runs on NVIDIA's GB200 NVL72 rack-scale systems, which combine GB200 Grace Blackwell Superchips in liquid-cooled configurations. The infrastructure choice suggests significant computational requirements for the model.

Codex, described as an "agentic coding application," represents OpenAI's push into AI agents for developer workflows. According to NVIDIA, the platform is designed for "processing information, solving complex problems, coming up with new ideas and driving innovation."

Technical Specifications Not Disclosed

OpenAI has not released specifications for GPT-5.5, including:

• Parameter count
• Context window size
• Benchmark scores
• Pricing structure
• Training data cutoff date
• API availability

The "5.5" designation suggests an intermediate release between major versions, though OpenAI has not confirmed whether GPT-5 itself has been released or if this represents a new naming convention.

NVIDIA Partnership

The deployment on NVIDIA infrastructure continues the close partnership between the two companies. NVIDIA's GB200 systems, announced in 2024, represent the company's latest generation of AI training and inference hardware.

The announcement notably comes from NVIDIA rather than OpenAI, with the full blog post truncated in the source material.

What This Means

This release confirms OpenAI is actively deploying new frontier models beyond GPT-4, though the lack of specifications and public API access suggests a controlled rollout strategy. The focus on agentic coding applications indicates OpenAI views developer tools as a key market for advanced models. The NVIDIA infrastructure requirement signals these models demand substantial computational resources, potentially limiting near-term availability. Without benchmark data or direct comparisons, GPT-5.5's capabilities relative to GPT-4 or competitors like Claude 3.5 Sonnet remain unclear.