The c6i.16xlarge pairs 64 vCPU with 128 GiB of RAM, the 2.00 GiB-per-vCPU ratio that marks a compute-optimized instance. In the name, "c" stands for compute, "6" is the generation, "i" marks Intel processors and "16xlarge" is the size within the c6i family. It runs on Intel Xeon 8375C (Ice Lake) at 3.5 GHz, and AWS introduced it in October 2021. AWS has since shipped c7i, c8i and c9g; c7i.16xlarge is the direct replacement at this size, scoring 1,461,076 CoreMark/s against this instance's 1,074,862 — roughly 36% more throughput for the same vCPU count. Spot's node ladder tops out below this size, so c6i.16xlarge becomes 4 × ch.vs1.2xlarge (64 vCPU, 128 GiB combined), about 94% below the US East (N. Virginia) on-demand rate. Spot delivers compute as managed Kubernetes, so a node pool of that size is the native shape of the answer rather than a workaround — provided the workload scales horizontally.
Match qualityScale-out match
c6i.16xlarge gives you 64 vCPU and 128 GiB in a single machine. The largest comparable Spot node, ch.vs1.2xlarge, is 16 vCPU and 32 GiB, so the equivalent here is 4 nodes rather than one.
Spot runs as managed Kubernetes, so a 4-node pool is the normal way to run things rather than a workaround. If your workload already sits behind a load balancer, a queue or a scheduler, it spreads across them without changes. If it needs all 64 cores and 128 GiB in one process, it does not.
