I am using Windows 8 64-bit and I have several USB thumbdrives. Whenever I try to copy files to any of them, the transfer starts out at about 17 MB/s, then goes to 19 MB/s, then drops to 5 MB/s and bounces between there and 3 MB/s. I have just updated my drivers and my computer has fairly new and fast hardware. These speeds are intolerable and I was wondering how to fix it.

I downloaded TeraCopy which has a precise percent progress bar, and I noticed that the transfer will start and stop, stuttering. About 7 MB will get transferred, then it will stop for about 2 seconds, and resume for 7 MB, and stop, until it's finished.

It should be noted that the rest of my computer is not slow at all, just copying to a USB drive takes an inordinate amount of time. I have looked at many of the related questions and cannot find any help.

I have tried using Device Manager to "Optimize the drives for performance" but that helped absolutely none. Some drives have a FAT32 filesystem, some have an NTFS filesystem, so I don't think that matters.

It seems like transferring to a USB stick used to be faster on my computer. Any ideas what it could be?

  • 1
    Do you use USB 2.0 or 3.0 drives? For USB 2.0 this are normal values of cheap USB thumb drives. – magicandre1981 Dec 2 '12 at 6:56

50% of common USB flash drives erase at 7MB/s or less. You probably just have cheap drives. They may have been faster in the past because until you write to each block at least once, erases aren't needed. After that, an erase is needed on every write.

See this table of performance numbers and look up your drive.


It is normal for windows to display an unusually fast transfer rate for a particular drive when the transfer has just begun, so the gradual yet steep decline in performance could simply the result of the header data being transferred before the transfer gets into the meaty stuff, at which time it often slows down. 3 Mbps is fairly low for USB 2.0 standards, but is fairly plausible. Many cheap drives have similar transfer rates. So to better troubleshoot your problem, I'd need you to first answer a few questions:

  • Does the drive use a USB 3.0 connection, and if so, is it plugged into a corresponding USB 3.0 port (if available). To determine this, check to see if both the male end (on your flash drive) and the female port (on computer) have a blue plastic interior lining. If not, try finding a blue port for both ends (if one is built into your PC). Of course this is all assuming you have a USB 3.0, which I doubt given by your transfer rate.
  • Have you tested the same drive in similar ports on a different computer (preferably one not running Windows 8 to eliminate that variable)? If not, do this and compare the data transfer rates. That way we can determine if this is an issue with hardware in drive, hardware in computer, both, or even software (though I doubt this).
  • Are you sure that data transfer rate used to be much faster, and do you think the decrease in performance coincided with when you upgraded to Windows 8?
  • Finally, if you could link the exact model of your drive, we could identify it to determine what the manufacturer states is the average transfer rate in conditions similar to yours, and then compare them to your own to determine (if you've tested on other computers and have gotten similar results) if it could be a hardware issue with the drive itself.

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