c5a.4xlarge

Analysis

The c5a.4xlarge is a compute optimized instance in the c5a 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 Mumbai instead of São Paulo saves $415 a month per instance: $0.3760/hour against $0.9440/hour, a 151% spread.

It is the cheapest of the 5 processor variants AWS sells at this size and generation. The c5n.4xlarge on Intel Xeon Platinum 8124M costs 40% more, and the c5.4xlarge, the c5ad.4xlarge and the c5d.4xlarge also sit above it.

At $0.6160/hour on demand in US East (N. Virginia), about $450 a month, the c5a.4xlarge is one of the cheaper ways to buy compute optimized capacity: only 14% of the 291 current compute optimized types cost less per vCPU-hour than its $0.0385.

Reserving it for a year with no upfront payment cuts the Linux rate to $0.3880/hour, which beats on demand once it runs more than 63% of the time; three years brings it to $0.2660/hour, 57% below on demand. Windows Server roughly doubles the bill at $1.35/hour, because the licence is charged per vCPU.

Looking beyond its own line, 4 of 31 current types with 16 vCPUs and similar memory are cheaper. The cheapest of those is the c6g.4xlarge on AWS Graviton2 at $0.5440/hour.