"Amazon released the latest generation of its public cloud service in January 2015. Cloud Spectator recently test the Elastic Cloud Compute (EC2) C4 family to evaluate any potential performance and price-performance improvements over its previous generation, the C3 family.
The results presented here indicate that the C4 virtual machines had 10 to 20 percent higher vCPU performance and approximately 6 GB/s more memory throughput than the C3 VMs across different machine sizes. However, after factoring in the price increases, the price-performance values of the C4 VMs averaged the same as the C3 VMs. Both vCPU performance levels and network throughput displayed high stability over time and across all tested machines. The results highlight Amazon’s effort to provide highly predictable performance outputs and to match its C4 family’s price-performance with that of its earlier generation C3 family."