r6i.4xlarge

Analysis

The r6i.4xlarge is a memory optimized instance in the r6i 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, 20% less ($147 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 r6id.4xlarge at $1.21.

At $1.01/hour on demand in US East (N. Virginia), about $736 a month, the r6i.4xlarge is one of the cheaper ways to buy memory optimized capacity: only 16% of the 385 current memory optimized types cost less per vCPU-hour than its $0.0630.

Running it in N. Virginia instead of São Paulo saves $438 a month per instance: $1.01/hour against $1.61/hour, a 60% spread.

The newer r7i.4xlarge on Intel Xeon Scalable (Sapphire Rapids) is 5.0% dearer at $1.06/hour.

Looking beyond its own line, 6 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.

It is size 4 of 9 in the r6i series. Stepping up to the r6i.8xlarge gives 32 vCPUs and 256 GiB for $736 more a month. Dropping to the r6i.2xlarge saves $368 a month.