The only thing I have in mind which could limit transfer speed is the bandwidth limit you can configure in the options dialog. It will limit the upload or download bandwidth or overall bandwidth on either side.
Please check if these settings are configured to be UNLIMITED.

Phex is created to download a file from multiple sources at once by using file segmentation. Therefore there is a certain overhead for managing segments, particulary for concatenating file segments. This will make Phex always slower compared to a direct file transfer between 2 computers on system level.

Gregor

__________________