AWS Lambda: Cold Start Duration per Instance Size

AWS Lambda has a setting to define the memory size that gets allocated to a single instance of a function. The CPU resources are allocated proportionally to the memory. So, in theory, larger instances could start faster.

However, there seems to be no significant speed-up of the cold start as the instance size grows.

Here is the comparison for a “Hello-World” JavaScript function:

Comparison of cold start durations per instance size, no dependencies

Here is the same comparison for a JavaScript function with 14 MB (zipped) of NPM packages:

Comparison of cold start durations per instance size, 14 MB (zipped) of dependencies

Here is the same comparison for a JavaScript function with 35 MB (zipped) of NPM packages:

Comparison of cold start durations per instance size, 35 MB (zipped) of dependencies

None of the charts shows a considerable advantage of larger instance sizes for the cold starts.

Go back to Cold Starts in AWS Lambda.