c7g.xlarge is AWS's compute-optimized EC2 size at 4 vCPU and 8 GiB. In the name, "c" stands for compute, "7" is the generation, "g" marks AWS Graviton (ARM) processors and "xlarge" is the size within the c7g family. It runs on AWS Graviton3 Processor at 2.5 GHz, and AWS introduced it in May 2022. AWS has since shipped c8g and c9g; c8g.xlarge is the direct replacement at this size, scoring 125,039 CoreMark/s against this instance's 99,782 — roughly 25% more throughput for the same vCPU count. On Rackspace Spot the same shape is ch.vs2.large — 4 vCPU, 8 GiB, matched on both dimensions, about 86% below the US East (N. Virginia) on-demand rate.
Match qualityx86 substitution
c7g.xlarge is Graviton (arm64). Rackspace Spot does not have arm64 servers, so ch.vs2.large is an x86_64 substitute with similar specs.
You will need x86 builds of your container images. Most software rebuilds without changes, but anything with compiled native code needs a real rebuild rather than a retag. Speed per core also differs between the two chips, so it is worth testing before deciding how many nodes to run.
