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I bought a 1 TB Seagate Backup Plus external HDD. It came with a single USB cable (USB 3.0 / 2.0 Backward compatible)

My laptop (Sony Vaio VPCEA33EN) has the follwing ports:

  • 3 × USB 2.0
  • HDMI
  • ExpressCard slot
  • SD Card slot
  • HG Duo slot

How can I get the maximum possible data transfer speed between my Windows 7 PC and the portable HDD I've bought?

I can buy cables and software, but I can't remove or add any hardware components to my system.

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If you cannot add any hardware, your maximum speed will be that of USB 2.0. AS you have an ExpressCard slot, why are you unable to add a USB 3.0 ExpressCard like this Startech one or something similar?

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The 1 TB Seagate Backup Plus hosts a 2,5 inch SATA disk internally, meaning the signal can be hooked up to a SATA-jack on your motherboard or an extrnal eSATA or eSATA/USB port, als known as eSATAp, instead of the casing interface. As a 2,5 inch drive, it can also receive power from the eSATAp port, even if this port does not support the optional 12 volt pins required to keep the phyiscally larger hard disks spinning.

Assuming SATA II, the interface would give you a maximum effective transfer rate of 2,4 Gb/s, as opposed to 0,28 Gb/s for USB 2.0 or 3,2 Gb/s for USB 3.0. These are theoretical limits. In practice, the HDD's throughput will not come close to maxing out these connections.

eSATAp cables that connect to the signal and power of 2,5 inch SATA drives are generally inexpensive. For the maximum transfer speed, you would have to open up the external drive's casing and connect the drive directly using a cable as in the image below. Though electronically compatible, keep in mind that SATA devices may not be designed to match the stricter eSATA requirements and may fail in hostile conditions.

eSATAp cable

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Might present a bit of a warrnty issue – Dave M Dec 26 '12 at 21:01

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