Why Does USB Flash Drive Transfer Speed Getting Worse

TukangUsapEmenq · January 30, 2019

Nah. Here's the point.

I've got a USB thumb drive, from Toshiba that got 4 GB of storage, with USB 2.0. Bought it for be like 8 years ago and still reliably functional (somewhat need a solder fix on the port, tho. Wiggling like crazy)

When I copy things into it, at least maximum speed of 10-15 MB/s (forget the exact number but it's good enough actually) for transfer speed, and it's stable, enough. Barely got spikes.

And then, I've got a deal of SandDisk CruzerBlade (original ofc), 32 GB and USB 2.0 too. Barely even touch 10 MB/s. Sometimes even the speed drops for a while. (not because of amount of small data copied, I know this really affect speed). Dunno why. Maybe the size of the drive affects speed either?

But. I did lend my friend's thumb drive (when I need it and didn't bring my own), at 4 or 8 GBs, same either. Barely touch 10 MB/s. And it's speed are spiking up and down like... Real hard.

Any explanation of this? I'm curious enough tbh. Different quality of flash memory or what?

Ashiella · January 30, 2019

35 minutes ago, dhannemon13 said:

Nah. Here's the point.

I've got a USB thumb drive, from Toshiba that got 4 GB of storage, with USB 2.0. Bought it for be like 8 years ago and still reliably functional (somewhat need a solder fix on the port, tho. Wiggling like crazy)

When I copy things into it, at least maximum speed of 10-15 MB/s (forget the exact number but it's good enough actually) for transfer speed, and it's stable, enough. Barely got spikes.

And then, I've got a deal of SandDisk CruzerBlade (original ofc), 32 GB and USB 2.0 too. Barely even touch 10 MB/s. Sometimes even the speed drops for a while. (not because of amount of small data copied, I know this really affect speed). Dunno why. Maybe the size of the drive affects speed either?

But. I did lend my friend's thumb drive (when I need it and didn't bring my own), at 4 or 8 GBs, same either. Barely touch 10 MB/s. And it's speed are spiking up and down like... Real hard.

Any explanation of this? I'm curious enough tbh. Different quality of flash memory or what?

Different quality of flash memory, and similar to SSD's, over-time and with lots of writes they will start to substantially slow down. (correct me if I'm wrong)

kirashi · January 31, 2019

21 hours ago, dhannemon13 said:

And then, I've got a deal of SandDisk CruzerBlade (original ofc), 32 GB and USB 2.0 too. Barely even touch 10 MB/s. Sometimes even the speed drops for a while. (not because of amount of small data copied, I know this really affect speed). Dunno why. Maybe the size of the drive affects speed either?

But. I did lend my friend's thumb drive (when I need it and didn't bring my own), at 4 or 8 GBs, same either. Barely touch 10 MB/s. And it's speed are spiking up and down like... Real hard.

Any explanation of this? I'm curious enough tbh. Different quality of flash memory or what?

20 hours ago, Ashiella said:

Different quality of flash memory, and similar to SSD's, over-time and with lots of writes they will start to substantially slow down. (correct me if I'm wrong)

No correction needed - you're basically correct here. Different brands (or even models / series) of drives can have different grades / qualities of flash NAND storage or controllers. These differences can cause anything from slower speeds to abnormal disconnects with some USB hubs running certain chipsets. (Even the USB ports in a computer technically run off an internal hub.) Plus, the flash NAND cells wear out over time, and copy at different speeds depending on the block size of the files themselves.