GPT-4.5: A Stopgap or a Glimpse into the Future?

2025-03-02
ℹ️Note on the source

This blog post was automatically generated (and translated). It is based on the following original, which I selected for publication on this blog:
GPT-4.5: “Not a frontier model”? – by Nathan Lambert.

GPT-4.5: More Questions Than Answers?

The release of GPT-4.5 by OpenAI has stirred a debate within the AI community, marked by a somewhat unusual disclaimer: "GPT-4.5 is not a frontier model." This statement, preceding any official announcement, has led to speculation about the model's intended purpose and its place in the ongoing evolution of large language models (LLMs).

One central paradox lies in the fact that GPT-4.5 represents the largest model accessible to the general public to date. Despite its scale, the jump in measured capabilities isn't as pronounced as the shift from GPT-3.5 to GPT-4, or even from GPT-4o to GPT-4.5. The improvements, while present, are subtle enough that discerning genuine advancements from perceived ones can be challenging. This raises the question: Is the relentless pursuit of scale beginning to yield diminishing returns in terms of tangible improvements for end-users?

What Makes GPT-4.5 Different?

Estimates suggest that GPT-4.5 boasts significantly more parameters and computational power than its predecessors. It's theorized that GPT-4.5 may have around 5-7 trillion parameters, with roughly 600 billion active parameters (similar sparsity to GPT-4). However, translating these increased parameters into readily apparent performance enhancements has proven complex.

OpenAI has highlighted improvements in areas such as world knowledge and question answering, showcasing advancements on benchmarks like KnowRef, PersonQA, and GPQA. Yet, when evaluated on code and technical tasks, GPT-4.5 has not consistently outperformed models like Claude 3.7 or R1.

Interestingly, in some subjective evaluations, users have even expressed a preference for the writing style of smaller, older models like GPT-4o. This could be attributed to factors like distillation, where smaller models are trained on the output of larger models, potentially leading to faster iteration speeds and refined post-training adjustments. Is the key not just size, but the way that size is utilized and refined?

The Price of Progress and the Future of Integration

GPT-4.5's pricing structure has also drawn attention, initially mirroring the high cost of the original GPT-4 launch. While these prices are expected to decrease over time, the current cost raises questions about the model's immediate accessibility and practicality for widespread use.

The release of GPT-4.5 may signal a shift in strategy. It's possible that OpenAI intends to leverage the model internally to train other models, indicating a move towards prioritizing reasoning models and refining existing capabilities rather than solely focusing on scaling. This aligns with research suggesting that scaling reinforcement learning (RL) training is more effective on larger models. Future iterations of models like o4 could then be distilled from these reasoning models trained on GPT-4.5.

The true potential of GPT-4.5 may lie not in its immediate impact as a standalone chatbot, but in its integration into broader AI systems and applications. The improvements in core capabilities could lead to more robust and versatile applications down the line. The development shows that AI progress requires constant adaptation, with frontier labs continuing to push the boundaries of scaling, even if the immediate benefits aren't always obvious. Which path will lead to the most meaningful advancements in the long run?


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