Usually it is small file that is slow in transfer because the hdd need to constantly seek for new file to transfer. This is a problem I never encounter so I don't think what to suggest. But may I ask if your large files are video file? If they are can you watch the video? Also is the large file transfer completed, although at a very slow speed or so slow that it freeze?
Can I assume you left both the sender and receiver drive all the speed it needs without running virus scan, hdd I/O intensive program in the background and the file transfer is unidirectional? Since the transfer is completed, I can rule out corrupted, crc error on file. Can you guestimate how long the transfer was and how big in total was the transfer. The transfer speed window indicates is often not accurate. So if you can calculate it yourself, it give a better speed estimation. Another thing I can think of is if your hdd is running at usb 1.1 speed (this is a very wild guess).