Pablo, from the SGD team, puts it this way: if you don’t name the difference, you end up “optimizing infra” when you are really redesigning the system, or the other way around.
Architecture is how you design the system. Design decisions: local sync vs Notion, NoSQL with indexes vs a CMS built for humans, the agent’s memory path, which queries you run, how skills and memory compose.
Infrastructure is where it runs and which resources keep it standing. RAM (~8GB in our case), Mac Mini vs provisioned cloud, ops costs, GPUs and clusters (as with Z.ai), provisioning, backups, and the price of keeping that stack on.
Z.ai is mainly about their inference infrastructure. The same cost/performance lesson shows up when you separate those design decisions from the infra bill.
For a growing company in Colombia, mixing the two layers gets expensive: you think you “need more cloud” when the bottleneck was the memory path… or you design a brilliantly fast path you cannot afford outside a Mac Mini.