r5b.xlarge

Analysis

The r5b.xlarge is a memory optimized instance in the r5b series with 4 vCPUs and 32 GiB of memory on Intel Xeon Platinum 8259 (Cascade Lake) (up to 3.1 GHz), which makes it memory-heavy at 8 GiB of memory per vCPU.

Within the same generation and size, the r5a.xlarge on AMD EPYC 7571 costs $0.2260/hour, 24% less ($52.56 a month). The other variants are the r5.xlarge at $0.2520, the r5ad.xlarge at $0.2620 and the r5d.xlarge at $0.2880.

Running it in N. Virginia instead of São Paulo saves $128 a month per instance: $0.2980/hour against $0.4740/hour, a 59% spread. It is not offered in Mumbai, so plan around that if you need a presence there.

On demand it costs $0.2980/hour in US East (N. Virginia), $218 a month if left running, which puts it mid-table for memory optimized types at the 40th percentile per vCPU ($0.0745 per vCPU-hour) and the 56th percentile per GiB ($0.00931 per GiB-hour).

Looking beyond its own line, 17 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 8 in the r5b series. Stepping up to the r5b.2xlarge gives 8 vCPUs and 64 GiB for $218 more a month. Dropping to the r5b.large saves $109 a month.