Related, from the article:

> We hypothesized that increasing the Node maximum heap size from the default 1.7GB may help. To solve this problem, we started running Node with the max heap size set to 6GB [..], which was an arbitrary higher value that still fit within our EC2 instances.

Sounds like they were utilizing their EC2 instances very poorly. Why not run more workers per instance, or switch to an instance type with less RAM (or more CPUs)?