https://www.theregister.co.uk/2018/01/04/amazon_ec2_intel_meltdown_performance_hit/

Amazon AWS customers have complained of noticeable slowdowns on their cloud server instances – following the deployment of a security patch to counter the Intel processor design flaw dubbed Meltdown.

Punters said that, since AWS began rolling out anti-Meltdown updates in December, they have noticed an increase in CPU utilization by their EC2 virtual machines. The solution is to either optimize the application code, or move to a more powerful and expensive host server to take the extra load.