...the TLDR is that we're training a 12-layer GPT-2 (124M), from scratch, on 10B tokens of FineWeb, with max sequence length of 1024 tokens.

The 124M model is the smallest model in the GPT-2 series released by OpenAI in 2019, and is actually quite accessible today, even for the GPU poor. With llm.c, which is quite efficient at up to ~60% model flops utilization, reproducing this model on one 8X A100 80GB SXM node takes ~90 minutes. For example, on Lambda this node goes for ~$14/hr, so the total cost of reproducing this model today is about $20. You can train the model with a single GPU too, it would just take proportionally longer (e.g. ~4-24 hours depending on the GPU).