Lambda functions are billed only for the time it actually runs. Increasing the memory also boosts CPU performance, but this raises the cost.Many of you might have adjusted the memory allocation while monitoring the execution time.AWS Lambda has a billing unit of 1 millisecond.Based on the tests conducted, single-task and multi-thread operations seem to only utilize a single core internally.From these results, we can see that increasing the number of processes beyond the number of vCPUs does not lead to further performance improvements.Since Lambda’s current limit is 6 vCPUs, there isn’t much benefit in parallelizing beyond that.AWS Lambda can now be expanded to up to 10GB of memory and 6 vCPUs.Once CPU performance reaches a certain level, additional vCPUs are assigned.With the recent update, there are cost benefits to pushing performance limits further.This article explores the relation between memory allocation, vCPUs and performance of Lambda function.