S5CMD numworker issue

[anudina]

Hi I am trying to download lot of files from S3 to local.
I am sending the command file like below
s5cmd run --numworker 256 commands.txt
and my commands file will have below sample of around 500 entries

eg: commands.txt

cp s3://XYZ/alprgagqenm-e-ec-c7kx-enmhost-1/abc.txt /home/test/copy/files/
I have literally like these around 500 entries in single commands.txt file
the same thing will be repeated untill all the files from S3 are downloaded like 10000 iteration.
What I am seeing is when I add records more than 70 its really taking a long to cp the files inspite of adding --numworker to 256 there is no impact.

1. what am I doing wrong or how does num-worker works?
2. Every number worker is 1 CPU on the server its running? for eg: i am running this on 80CPU 256GB gaint box.
   provide some insight to tweak this pls.

[rmanus]

You might be exhausting your network bandwith with so many workers.