I was running all my containers on AMD64 shapes because that's what I'd always done. x86, Intel/AMD, the default. Then I looked at my OCI bill and realized I was paying $0.064/OCPU/hr for AMD64 when ARM shapes cost $0.010/OCPU/hr. Six times cheaper for the same work. The catch? My Docker images were all built for AMD64. They wouldn't run on ARM nodes. I had to figure out multi-arch builds. It took me an afternoon to get right, and now every image I build supports both architectures. Here's what I learned. Why ARM on OCI Is Different From ARM Everywhere Else AWS has Graviton. GCP has Tau T2A. Azure has Ampere Altra. They're all ARM, and they're all cheaper than their x86 equivalents. But OCI's pricing gap is the widest I've seen: Architecture Shape $/OCPU/hr 4 OCPU + 24GB monthly ARM VM.Standard.A1.Flex $0.010 ~$29 AMD64 VM.Standard.E4.Flex $0.064 ~$184 And the Always Free tier gives you 4 ARM OCPUs and 24GB RAM forever. There's nothing comparable on the x86 side.…