r6in.4xlarge

Analysis

The r6in.4xlarge is a memory optimized instance in the r6in series with 16 vCPUs and 128 GiB of memory on Intel Xeon 8375C (Ice Lake) (up to 3.5 GHz), which makes it memory-heavy at 8 GiB of memory per vCPU.

Within the same generation and size, the r6g.4xlarge on AWS Graviton2 costs $0.8064/hour, 42% less ($429 a month), though switching means rebuilding software for arm64. The other variants are the r6a.4xlarge at $0.9072, the r6gd.4xlarge at $0.9216 and the r6i.4xlarge at $1.01.

Running it in N. Virginia instead of Sydney saves $219 a month per instance: $1.39/hour against $1.69/hour, a 21% spread. It is not offered in São Paulo, London and Mumbai, so plan around that if you need a presence there.

On demand it costs $1.39/hour in US East (N. Virginia), $1,018 a month if left running, which puts it mid-table for memory optimized types at the 61st percentile per vCPU ($0.0872 per vCPU-hour) and the 76th percentile per GiB ($0.0109 per GiB-hour).

Looking beyond its own line, 29 of 42 current types with 16 vCPUs and similar memory are cheaper. The cheapest of those is the r7g.4xlarge on AWS Graviton3 at $0.8568/hour.

Reserving it for a year with no upfront payment cuts the Linux rate to $0.8786/hour, which beats on demand once it runs more than 63% of the time; three years brings it to $0.5647/hour, 60% below on demand. Windows Server roughly adds 53% to the bill at $2.13/hour, because the licence is charged per vCPU.