What does ECU units, CPU core and memory mean when I launch a instance

Question

When I launch an instance on EC2, it gives me option for t1.micro, m1.small, m1.large etc. There is a comparision chart of vCPU, ECU, CPU cores, Memory, Instance store. Is this

Answer 1

Responding to the Forum Thread for the sake of completeness. Amazon has stopped using the the ECU - Elastic Compute Units and moved on to a vCPU based measure. So ignoring the ECU you pretty much can start comparing the EC2 Instances' sizes as CPU (Clock Speed), number of CPUs, RAM, storage etc.

Every instance families' instance configurations are published as number of vCPU and what is the physical processor. Detailed info and screenshot obstained from here http://aws.amazon.com/ec2/instance-types/#instance-type-matrix