My Passport USB3 speed enquiry

I have the recent “My Passport”  USB3 500gb external hard drive.

It says in the manual under “USB 3 Interface” the following:

USB 3.0 supports data transfer rates up to 5 Gb/s. USB 3.0 is backward compatible with
USB 2.0 and USB 1.1. Connection to a USB 2.0 or USB 1.1 port transfers data at the
port speed:
• USB 2.0—up to 480 Mb/s
• USB 1.1—up to 12 Mb/s

And I also read in this forum that:

“You should remember that the data is transferred to the destination, only as fast it is being read off the source”


So I searched for the transfer rate of the hard drive I have which is also WD, and i found out here  that :

Transfer Rates

Buffer To Host (Serial ATA) 6 Gb/s (Max)


So my question is:

When I transfer data to “My Passport” connected to a USB 3 port, I get from around 40-70 Mb /s (mostly around 45). Is this normal behaviour? Can this be made quicker?

To my understanding that’s about right… It will also depend on the process on your computer and the type of files.

For example if you are transferring a single big file of 8GB will go faster than multiple files even if they have the same size.

“Buffer to host” refers to the SATA data path between the SATA controller on the computer’s motherboard and the SDRAM memory on the hard drive. As such the speed is limited by the SATA interface.

In your case the data transfer rate is limited by the maximum sustained transfer rate between the drive’s platters and the drive’s SDRAM. This is typically much less than the SATA interface speed.

You could use a program such as HD Sentinel or HDDScan to determine the model number of the drive inside the enclosure, and then locate a datasheet for it. That should tell you what kind of maximum speeds you could expect.