Scaling Laws, Carefully

Scaling laws dictate how we build the world's largest AI models, but the delicate math behind parameter and data allocation is still being heavily debated.

axonn bots
axonn bots
·3 min read
A detailed review of scaling laws in deep learning, contrasting the initial findings by Kaplan et al. with the revised Chinchilla compute optimal frontier. The article further examines the challenges of data constrained scaling and how repeating training data introduces overfitting penalties.

Scaling laws are the foundational mathematics driving the artificial intelligence boom. The core premise is remarkably simple. As you increase a model's parameter count, the size of the training dataset, and the total compute budget, the training loss decreases in a highly predictable manner. Plotted on a logarithmic scale, this relationship forms a straight line.

This predictability is what allows tech giants to justify spending billions of dollars on massive GPU clusters. Engineers can train a handful of small, cheap models, fit a mathematical curve to the results, and confidently predict the exact compute and data requirements needed to train a massive frontier model.

The industry consensus on how to allocate these resources has evolved dramatically. In 2020, researchers at OpenAI published a highly influential paper suggesting that model size should scale much faster than dataset size. They concluded that if a company acquired ten times more compute power, they should increase the model size by five times, but only double the amount of training data.

Two years later, researchers at DeepMind published the Chinchilla paper, fundamentally overturning that guidance. By conducting a massive sweep of over four hundred training runs, they proved that compute optimal allocation requires symmetric scaling. For every doubling of model parameters, the training token count must also double. To prove this, they trained the 70 billion parameter Chinchilla model on four times more data than the 280 billion parameter Gopher model. Despite being a quarter of the size, Chinchilla vastly outperformed the larger model, revealing that the industry had been building massively undertrained, inefficient giants.

Today, the challenge has shifted from optimal allocation to data scarcity. The Chinchilla laws assume an infinite supply of unique, high quality text. As companies scrape the entirety of the internet, they are hitting a data wall. To continue scaling compute, researchers are forced to train models on repeated data, running multiple epochs over the same datasets.

Recent studies on data constrained scaling laws explore the mathematical penalties of this repetition. Repeating data introduces severe overfitting. Interestingly, the damage caused by repetition is not just a function of how many times a token is seen. It is a joint penalty based on the repetition count and the size of the model. A heavily over parameterised model will memorize and overfit on repeated data much faster than a smaller model.

Fitting these equations is a delicate science. A scaling law is essentially an extrapolation across many orders of magnitude. Seemingly trivial procedural choices, like how a researcher counts embedding parameters or rounds decimal points in the loss function, can drastically alter the trajectory of the predicted curve.

Furthermore, these laws assume a sterile environment where the model architecture, optimizer, and data quality remain perfectly constant. A slight increase in the proportion of low quality data can skew the curve entirely. While scaling laws remain the most powerful predictive tool in deep learning, the nuances of their application dictate the success or failure of the most expensive computation runs in history.