We're sorry to hear about the lower transfer speeds. The drive has sequential read speeds up to 560MB/s and write speeds up to 520MB/s, however actual performance can vary depending on the host device and usage conditions. We recommend backing up the data and reformatting the drive (steps: https://support-en.sandisk.com/app/answers/detailweb/a_id/20821). Kindly ensure to backup your data before reformatting since it is a data-destructive process. If the issue persists, please get in touch with our support team for further assistance by opening a ticket at (https://support-en.sandisk.com/app/askweb)