How does memory allocation impact processing time while using AWS lambda

Question

I have a Lambda function and its taking about 120ms with 1024mb memory size. I then checked the logs and found out that it was using only 22mb at max, so I tried optimizing it by reducing to 128mb.

But when I did that the time went from 120ms to 350ms and only 22mb memory was being used. So, i am a bit confused. How does memory allocation impact processing time.

Answer 1

The underlying CPU power is directly proportional to the amount of memory that you choose. So basically that memory knob controls your CPU allocation as well.

So that is the reason why you are seeing that reducing the memory causes Lambda to take more time for execution