I bought a Seagate Expansion portable disk (1 TB).

I am using a Dell Inspiron 15R (5521) laptop which has 2 usb 3.0 ports. But when I transfer files to my above mentioned portable drive I do not get a transfer speed of more than 35 MB/s. Sometimes the speed is slower than that. What is the issue here, and how do I fix it?

  • 3
    Are you sure your using the USB 3.0 port instead of the USB 2.0 port? Furthermore what makes you think 35MB/sec isn't fast compared to the speeds of a USB 2.0 device it would actually be several times faster. In addition because its a mechanical HDD there are speed limitations connected to that fact.
    – Ramhound
    Aug 21 '13 at 11:11

I had the same problem but I only managed to fix it on the dekstop, not my laptop. I plugged it into a different port (at the back). The front blue ports were doing only 35-40 MB/s. The back port is proper. The difference between the port is if they belong to your chipset or if there is a dedicated chip for those USB3 ports.

Use "USB Device Tree Viever" free software to see this:

enter image description here

You can see that some controllers only do USB 2. But I first tried it in the bottom one which is an Intel. I'm currently looking for drivers for that because it's not so convenient to plug the external disk to the back of the desktop PC everytime. I understand if your laptop doesn't have more than 1-2 controllers, but it's worth a try to go through all possible ports.

Previously it looked like this (hard limit due to wrong or misconfigured USB controller):

enter image description here

Now it looks like this (nothing is wrong with the drive):

enter image description here

This seems like a nice guide and program to update your drivers.

  • 1
    I always thought the blue ports were USB 3.0 indicators, turns out that's not true at all. Learned yet another thing! That USBTreeView tool is incredibly useful by the way.
    – xorinzor
    Apr 8 '20 at 17:38

The common causes are:

  • cable
  • driver
  • USB2 port

So make sure it's a USB3 cable from end to end and try a different one in case it's just a bad cable. Then update the drivers to the latest for your USB3 hardware. Finally try both USB3 ports on your laptop (looks like they are the two on the left furthest away from the audio jack).

  • The cable is usb 3.0, and it is brand new. Even if I try to transfer files to a flash drive using usb 3.0 the speed is very low
    – DesirePRG
    Aug 21 '13 at 11:40

Intel make only one driver for usb3 with Windows 8. This driver downgrades the transfer speeds to the lowest common denominator within the system. In other words, if it senses any usb2 device or a faulty/substandard usb3 device, the fastest your usb3 system will transfer data at will be at a self determined (Intel usb3 driver) speed.
So, try removing all other usb devices and see what speeds you get! I'll bet it takes off like a rocket (on the assumption your new portable drive is 100% ok).
Finally, the Intel usb3 driver seems to be extra sensitive so don't expect data transfer rates to be at the theoretic/quoted possible speeds. That's a pipe dream but never the less, will be much faster than usb2.

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