Virtual CPUs with Amazon Web Services

Some months ago, Amazon Web Services changed the way they measure CPU capacity on their EC2 compute platform. In addition to the old ECUs, there is a new unit to measure compute capacity: vCPUs. The instance type page defines a vCPU as “a hyperthreaded core for M3, C3, R3, HS1, G2, and I2.” The description seems a bit confusing: is it a dedicated CPU core (which has two hyperthreads in the E5-2670

[yass]

" A vCPU in an AWS environment actually represents only half a physical core. So if you’re looking for equivalent compute capacity to, say, an 8-core server, you would need a so-called 4xlarge EC2 instance with 16 vCPUs. "