Note: This topic is similar to one on OneDrive edge location selection. Merge if appropriate.
Amazon introduced S3 Transfer Acceleration last month. It is a transparent method of using Amazon’s edge network to speed up transfers to or from an S3 bucket. It costs extra to use this feature, but it significantly improves transfer speeds when the bucket endpoint is distant. We are near Amazon’s US-West-2 facility, so no improvement when uploading from our office. Try the same from SE Asia and uploads are over 10x faster. That’s enough to notice.
I know that Amazon has hooks to allow third party programs to switch between normal and accelerated buckets on the fly. We use CloudBerry Backup and there is an option to switch between normal S3 transfers and using the S3 Accelerator on the same S3 bucket.