c5ad.4xlarge

Analysis

The c5ad.4xlarge is a compute optimized instance in the c5ad series with 16 vCPUs and 32 GiB of memory on AMD EPYC 7R32 (up to 3.3 GHz), which makes it compute-heavy at 2 GiB of memory per vCPU.

Running it in N. Virginia instead of São Paulo saves $280 a month per instance: $0.6880/hour against $1.07/hour, a 56% spread. It is not offered in Canada Central, London, Mumbai and Tokyo, so plan around that if you need a presence there.

Within the same generation and size, the c5a.4xlarge on AMD EPYC 7R32 costs $0.6160/hour, 10% less ($52.56 a month). The other variants are the c5.4xlarge at $0.6800, the c5d.4xlarge at $0.7680 and the c5n.4xlarge at $0.8640.

On demand it costs $0.6880/hour in US East (N. Virginia), $502 a month if left running, which puts it mid-table for compute optimized types at the 28th percentile per vCPU ($0.0430 per vCPU-hour) and the 32nd percentile per GiB ($0.0215 per GiB-hour).

Reserving it for a year with no upfront payment cuts the Linux rate to $0.4330/hour, which beats on demand once it runs more than 63% of the time; three years brings it to $0.2970/hour, 57% below on demand. Windows Server roughly doubles the bill at $1.42/hour, because the licence is charged per vCPU.