Windows WSL (Ubuntu 20.04) aws s3 cp command slows drastically when downloading to external drive, while other methods aren't affected

Question

Was hoping someone might be able to explain whats going on here:

I have been trying to download large files from AWS S3 to my local computer.

Using standard:

aws s3 cp s3://my-big-file.file ./

I'm getting ~70 MiB/s

When downloading to an external drive, I suddenly drop to around ~10 Mib/s.

aws s3 cp s3://my-big-file.file /mtn/d/

At first, I thought ok this makes sense, the external drive is throttling me.

However, using S3Browser, downloading to the external drive, I'm getting ~70 MiB/s.

This is frustrating because I'm trying to automate downloads of projects... and can't with the S3Browser.

Any thoughts?

Thanks!

EDIT: I went ahead and installed AWS CLI for Powershell.

The aws s3 cp command is also as fast as S3Browser, so it seems there is some bottleneck with WSL. For now I plan to just write a script in powershell, but I'm still curious to know whats the cause of this!