A practical framework for choosing between TPUs and GPUs for AI/ML workloads, covering silicon architecture differences, use-case fit, and total cost of ownership. TPUs excel at large-scale JAX-based pretraining (100B+ params) on GCP with committed-use discounts, but their static shape requirements, GCP-only availability, and smaller ecosystem make GPUs the default for most teams. GPUs dominate due to PyTorch/CUDA ecosystem maturity, dynamic shape support, multi-cloud portability, and viable spot automation. The post also covers GPU cost optimization strategies including rightsizing via DCGM, spot instance automation, MIG partitioning, and inference density improvements, with Cast AI promoted as a solution for automating these optimizations.
