r4.xlarge

Analysis

The r4.xlarge is a memory optimized instance in the r4 series with 4 vCPUs and 30.5 GiB of memory on Intel Xeon E5-2686 v4 (Broadwell) (up to 2.3 GHz), which makes it memory-heavy at 7.62 GiB of memory per vCPU.

Running it in N. Virginia instead of São Paulo saves $215 a month per instance: $0.2660/hour against $0.5600/hour, a 111% spread.

On demand it costs $0.2660/hour in US East (N. Virginia), $194 a month if left running, which puts it mid-table for memory optimized types at the 28th percentile per vCPU ($0.0665 per vCPU-hour) and the 47th percentile per GiB ($0.00872 per GiB-hour).

The newer r5.xlarge on Intel Xeon Platinum 8175 is 5.3% cheaper at $0.2520/hour, which makes the r4.xlarge hard to justify for new deployments.

Looking beyond its own line, 12 of 45 current types with 4 vCPUs and similar memory are cheaper. The cheapest of those is the r6g.xlarge on AWS Graviton2 at $0.2016/hour.

It is size 2 of 6 in the r4 series. Stepping up to the r4.2xlarge gives 8 vCPUs and 61 GiB for $194 more a month. Dropping to the r4.large saves $97.09 a month.

Reserving it for a year with no upfront payment cuts the Linux rate to $0.1680/hour, which beats on demand once it runs more than 63% of the time; three years brings it to $0.1145/hour, 57% below on demand. Windows Server roughly adds 69% to the bill at $0.4500/hour, because the licence is charged per vCPU.