EC2 bandwidth to the Internet

Whilst some instance types can clearly deliver 10Gbps or more of bandwidth you can't use all of this for internet-bound traffic. You should expect to see the following limits on internet egress bandwidth per instance:

• Single Flow from one instance - 5Gbps
• Multiple Flows from one instance - 5Gbps

In many scenarios, multiple flows from an instance can hit much higher limits (e.g. 25Gbps to S3, or over VPC Peering links), but for Internet egress there is a 5Gbps cap per instance. You can find this in the public documentation here:

Network traffic outside a cluster placement group (e.g. to the Internet) is limited to 5 Gbps (full duplex)