The resource triangle
Every deep-learning project sits inside a triangle of data, compute, and hardware. Move one and the other two reorganize. More data without more compute is wasted; more compute without more data overfits; better hardware widens the design space but does not invent new ideas.
Knowing which corner is binding for your project is half the job. A small startup usually has a data corner that bites first. A research lab usually has a compute corner. A solo hobbyist on a single GPU has a hardware corner that turns "let's try a 70B model" into "let's quantize an 8B model and tune the prompts."
What the hardware actually does
GPUs and TPUs are tensor accelerators: they multiply matrices and apply elementwise operations very fast in parallel. Modern accelerators (NVIDIA H100, Apple Silicon GPU/ANE, Google TPUv5) add specialized features for low-precision math (FP16, BF16, FP8) and for the attention pattern. Deep-learning frameworks exist to translate your high-level Python into the kernels these chips actually run.
What scaling looks like in practice
The empirical scaling laws (Kaplan et al., Chinchilla) tell you roughly how loss decreases as you add parameters and tokens — bigger models trained on enough data keep improving in a predictable way. This is why the field's biggest gains have come from scaling existing recipes rather than from inventing new ones.