AI training time is at a point in an exponential where more throughput isn't going to advance functionality much at all. The underlying problem, problem solving by training, is computationally ...
Large language models can write essays, summarize legal clauses, explain ancient history, draft emails, and produce code that looks impressively official. Then you ask one to multiply two awkward ...
If you start naively without any library that avoids the problem then memory access is the problem. Have a look at how much effort is needed to avoid the problem, for example with blocking algorithms.