Very high CPU steal after moving instance from eu-west-1 to eu-west-2

Hi,

I took an AMI of an EC2 instance in eu-west-1 and moved it to eu-west-2.

Since then, I have been experiencing intermittent, but very severe, CPU steal.

I suspect there is a noisy neighbour on the new London hypervisor as I changed nothing else (same instance size etc).

See attached graph. The times are in UTC. The white gap is the time where I stopped the eu-west-1 instance (data on the left of the gap) and spun an AMI of it up at eu-west-2 (data on the right of the graph).

https://imgur.com/a/R56dKyq

The instance id is i-0bbb311336550f3e9

Any ideas? Can an engineer check for any other EC2 guest on this hypervisor at the shown times in the graph to see if there was excessive activity?

Or are ECUs clocked/throttled differently at eu-west-2 even for the same t2.micro instance type?

Thanks