- The capability of any other drives involved in a file transfer.
- The slowest bus involved in the transfer.
- Any older technology involved in the transfer.
The capability of any other drives involved in a file transfer
If you are transferring from an internal drive, be aware that you will not be able to exceed the speed of that drive. If you are transferring data to the Seagate Fast from a standard drive inside the computer, the transfer speeds and access time will be limited to the maximum performance of the internal drive.
The best case scenario is to transfer files between other SSDs for peak performance, such as from an SSD boot drive to the Fast drive, or from one Fast drive to another.
The cabling interfaces involved in the transfer
Here are some common examples of potential bottlenecks.
- A transfer between a Fast drive and a drive connected via a USB 2.0 port or hub will be limited to USB 2.0 speed (less than 40MB/s).
- A transfer between a Fast drive and a drive connected to a USB 3.0 card plugged into a PCI Express 1.0 1x slot will be limited to 250MB/s maximum (about 200MB/s maximmum with command and error correction overhead).
- A transfer between a Fast drive and an internal drive connected on a 1.5Gb/s SATA controller will be limited to 150MB/s maximum.
- A transfer between a Fast drive and an internal drive connected on a 3Gb/s SATA controller will be limited to 300MB/s maximum.
- Two USB 3.0 drives that are connected on the same USB 3.0 root hub they will share 5Gb/s total possible bandwidth.
It is optimal to connect the Fast drive directly into a USB 3.0 port attached to the computer’s motherboard (no front USB ports or hubs), then perform transfers from an SSD connected to a motherboard with SATA 6Gb/s capabilities.
Any older technology involved in the transfer
As mentioned above, older technology like PCI Express 1.0, USB 2.0, or SATA 1.5Gb/s can limit transfer rates substantially. Use a system with the latest technology for best performance.
Windows 8, Mac OS 10.8+, and USB 3.0 have a protocol called UASP (USB-Attached SCSI Protocol) which will minimize command and error correction overhead and allow transfers to get a little more performance than obtainable by the standard USB 3.0 interface. To achieve the highest performance with UAS, you would need:
- a USB 3.0 port that supports UAS,
- an operating system that supports UAS (Windows 8 or Mac OS 10.8), and
- a device that supports UAS (like Seagate Fast).