[cmwright]

We played with this a bit using both cloudfront and other cdns. While we did see some small improvements, it wasn't nearly as good as we were expecting on the upload side. It may be fixed now, but there were also many issues getting the proper headers to pass through cloudfront to s3 for chunked uploads.

[samstave]

This might not be the right question, but:

Did you test using S4CMD with many threads as opposed to S3CMD?