WD My Passport Ultra 5 TB speed on Mac

Hello WD Community,

I purchased the WD My Passport Ultra 5 TB drive. it cam pre-formatted for windows. I reformatted it to APFS in Disk Utility.

The drive works great – I’m trying to understand how fast it SHOULD run…
I want to use my M1 Mac Mini’s Thunderbolt port for maximum speed.

The Blackmagic Disk Speed Test app shows 120 MB/sec read and write speeds on my new 2020 M1 Mac Mini on USB 3.0. I was unable to connect the drive to the Mac’s Thunderbolt port with the included cable. After buying a USB-C Thunderbolt 3 cable on Amazon , I STILL see 120 MB/sec read and write speeds using the Thunderbolt ports.

Is this the expected speed of he drive? I have tried asking WD Support directly via email, but they have only provided “theoretical” max USB speeds, which is not what I am asking.

This is the USB-C cable I purchased on Amazon. The cable works, but is this the best speed I should expect??
ANNNWZZD Thunderbolt 3 Cable 40Gbps Data Transfer 100W Charging(20V, 5A) USB Type-C Cable,USB 3.1 Compatible [Thunderbolt 3 Certified] (2.6ft)
Amazon.com: ANNNWZZD Thunderbolt 3 Cable 40Gbps Data Transfer 100W Charging(20V, 5A) USB Type-C Cable,USB 3.1 Compatible [Thunderbolt 3 Certified] (2.6ft): Computers & Accessories

I’ve never had any problems with any WD My Passport drives I’ve owned, so I’m happy to overlook the extra cost of buying a cable.

I appreciate any help I can get!

I believed if they are not SSD drive then you will not get the transfer at Thunderbolt speed. As you noticed your drive is a mechanical drive (spinning disks).

Yes, the WD drive is a physical disk drive, NOT an SSD. The speed the disk reads and writes is limited by the physical disk itself, not the Thunderbolt interface. So I am asking what read and write speeds (not disk RPM speed, or USB maximum theoretical speed) I should expect.

For example, I purchased a SanDisk Extreme Pro 1 TB SSD drive. It is rated as “Up to 1000 MB/sec read and write”. When I test it on my Mac, it runs at 850-895 MB/sec on Thunderbolt, and 360-390 MB/sec on USB 3.0. This is an example of how the read and write speeds are limited by the device and the interface. Also, since I am seeing speeds close to the maximum (850-895 is close enough to 1000), that lets me know my Mac and cables are getting the most out of the drive.

I am trying to learn how fast the WD physical disk will run read and write operations. Since I see the same speeds of 110-120 MB/sec on BOTH the USB3 and Thunderbolt, I am wondering if I have the correct Thunderbolt cable to enable higher speeds, or if the 110-120 is as fast as the drive can work, regardless of the interface. Does that make sense?