What are the new features of GPT-5?
OpenAI describes GPT-5 as “the smartest and most useful model yet—with built-in reasoning that makes expert knowledge accessible to everyone” (OpenAI, 2025). According to the official GPT-5 system card, OpenAI describes GPT-5 as “a unified system with a fast model, a deeper reasoning model (GPT-5 Thinking), and a real-time router that quickly decides which model to use based on the type of conversation and complexity.” The “router” is an administrative layer or decision-making logic, not necessarily a standalone “hardware router” in the traditional sense. The model to be used is decided on a per-prompt basis. The model promises shorter response times and more stable performance, while also offering longer dialogue times and personalized responses. Here is an overview of the most important new features, based on OpenAI's release blog:
Improved accuracy and speed: more precise answers and faster responses than its predecessors, especially in the fields of mathematics, science, finance, and law.
Optimized programming capabilities: introduction of GPT-5 Codex as a specialized model for demanding programming and debugging tasks, a model that has been specifically trained for coding agent tasks; it is used in development environments and is also available to companies via the API. In general, the standard GPT-5 model has significantly improved programming capabilities compared to GPT-4o
Advanced creative writing: GPT-5 transforms raw ideas into compelling, impressive texts with literary depth and rhythm
Improved health literacy: HealthBench scores significantly higher than all previous models, based on realistic scenarios and criteria defined by doctors.
Advanced context processing: The extended token context window allows GPT-5 to engage in longer and more complex conversations.
New model variants: Specialized variants such as GPT-5 mini and GPT-5 nano are optimized for specific tasks
Enhanced security features: GPT-5 Codex includes both model-level mitigations (e.g., training against malicious tasks and prompt injections) and product-level protections such as sandboxing and configurable network access.
This makes GPT-5 more versatile for use in a wide variety of areas, from content creation and programming to business analysis. The following graphic demonstrates the system architecture and underlying models for GPT-5:
While companies and developers welcome this potential, critics are increasingly voicing concerns about data protection and social implications.
Versions and Usage of the GPT Models
Here an overview of the current models of OpenAI's GPT used:
GPT-5 represents the continuous evolution of OpenAI's AI models. GPT-4 laid the foundation with advanced text and image processing and reliable accuracy in everyday tasks. GPT-4o, as a turbo-optimized variant, worked faster and more accurately and also experimented with audio and video processing, as well as empathetic and emotional voice. GPT-5, the latest version of the generation, combines the highest accuracy with native multimodality for text, image, audio, and video, as well as an extremely large context window. The choice of model ultimately depends on the required accuracy and model capacity for each use case.
GPT-5 is available with free access (limited quota) and with full access in professional plans. GPT-4, GPT-4o, and other models in the GPT-4 family will be phased out by mid-February, allowing OpenAI to focus primarily on expanding the new generation and further developing the GPT-5 models.
Also new: ChatGPT Go, a new, affordable subscription tier between Free and Plus, is launching, significantly broadening access – strategically well-positioned just before the planned advertising rollouts. In parallel, OpenAI is officially announcing for the first time the introduction of advertising in ChatGPT, particularly through "Sponsored Recommendations" for Free and Go users.
GPT-5 vs. GPT-4/4o
GPT-4 already represented a major leap in AI-powered text and image processing, GPT-5 now sets new standards in accuracy and performance. GPT-4 offers developers and businesses a powerful platform for applications in text processing, chatbots, content generation, and much more. GPT-5 significantly expands these capabilities: While GPT-4 Turbo and GPT-4o already supported multimodality, GPT-5 allows for audio and video content in addition to text and images, offers a significantly larger context window, and introduces the new Thinking Mode. Furthermore, the standard GPT-5 model has significantly improved programming capabilities compared to GPT-4.
GPT-5 Models Overview
The GPT-5 model series comprises several clearly defined variants that differ in computational effort, reasoning depth, response quality, and application focus.
GPT-5: the default basis for generally demanding AI tasks; the model combines several components and introduces an adaptive architecture system.
GPT-5.1: an upgrade of GPT-5 with improved personality settings and instructional behavior; however, it is only offered as a legacy option in ChatGPT (short transition period).
GPT-5.2: the current leading model generation, released in December 2025. It introduced significant improvements in reasoning and professional knowledge work and is the standard model for ChatGPT-Pro/Business plans and API
Codex variants: GPT-5 Codex (with version 5.2) is a specialized GPT-5 variant for agent-based coding and optimized for complex programming and cybersecurity via Codex platforms and Codex CLI/IDE integration.
GPT-5 Pro also represents an enhanced, more powerful variant of the GPT-5 system, specifically designed for the most demanding and complex tasks. The main difference between the GPT-5 (Standard) and GPT-5 Pro plans lies in computing power and processing time. The Pro version is primarily aimed at professional users, developers, and researchers who require advanced features. It relies on parallel use of computing resources for maximum precision, which can result in longer response times of up to five minutes (TechRadar, 2025). Topics can be combined and creatively synthesized. The model costs $200 per month, but for this price offers 80% fewer errors on complex queries compared to GPT-4 and a performance increase from 6.3% to 24.8% in expert tests thanks to the "Thinking" mode. (Vellum, 2025)
GPT-5 under discussion: Why is the model so polarizing?
As with any major AI innovation, GPT-5 is also causing debate. The topics of ethics and security are particularly polarizing, but so is transparency. OpenAI does not present GPT-5 as a fundamental innovation, but rather as a moderate continuation of GPT-4 in terms of its performance and capabilities. Spectacular leaps and revolutionary capabilities are therefore not to be expected, but rather iterative developments. The disappointed perception of GPT-5 seems to be based on overly high expectations and hype. In the Effective Altruism forum, where technical and ethical aspects in particular are discussed intensively, it is referred to as a family model plus router: “It's more of a product release: a family of models plus a router.”
User reactions to the router model can be seen in the post on X by Nick Turley, Head of ChatGPT and a key figure behind the product strategy and development. His online presence (@nickaturley on X, formerly Twitter) is a regular part of the public debate on GPT versions and AI directions, as was the case with the release of GPT-5. Particular criticism has been directed at the testing of GPT-5's safety routing decisions, which Nick Turley also highlighted on X:
Security routing automatically censors sensitive/emotional chats for paying adults and severely restricts creative and emotional nuances by automatically switching from GPT-4/o to GPT-5. Users criticize this, partly due to strong attachments to earlier models, and are consequently demanding protective measures and options such as opt-out, clear notices, and routing protocols (see Reddit). Overall, discussions on the web reflect that while GPT-5 delivers progress, many observers remain skeptical about how “revolutionary” and transparent these advances are.
Current developments and Outlook
The introduction of a hybrid multi-model system enables more efficient task distribution and leads to improved performance for complex queries. Benchmark tests confirm higher accuracy and reduced error rates compared to previous models.
"GPT-5's strengths lie primarily in agentic applications, especially in the area of in-depth research and as an assistant in programming."
Patrick from moinAI, CEO & Head of Research
What about gpt-oss?
With less buzz in the general news world, we at moinAI are very excited about the open source model gpt-oss. This was introduced in the same week as the GPT-5 models. The advantage of the oss variant for moinAI as a SaaS provider is that it is very fast and performs similarly to the popular GPT-4o model. This makes it possible to offer the service at its current excellent level, hosted entirely on German servers at moinAI, without dependence on providers such as OpenAI or Azure. This ensures that customer data is never passed on to third parties.
What can we expect from future models?
Future models such as GPT-6 could therefore have better personalisation features to respond to individual user preferences, as well as further increasing the context window and offering even more accurate multimodality. However, exact values are not yet available, and the official announcement of GPT-6 and its specific features remains to be seen.
GPT-5 already marks a significant advance in AI development, but there are complaints about lower transparency and control compared to previous models, and responses are perceived as too formal and less appealing. OpenAI needs to address this feedback and incorporate it into future releases.
