PV vs HVM

"Linux Amazon Machine Images use one of two types of virtualization: paravirtual (PV) or hardware virtual machine (HVM). The main differences between PV and HVM AMIs are the way in which they boot and whether they can take advantage of special hardware extensions (CPU, network, and storage) for better performance.

For the best performance, we recommend that you use current generation instance types and HVM AMIs when you launch your instances. For more information about current generation instance types, see Amazon EC2 Instance Types."

Reference: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/virtualization_types.html