Expected transfer speeds between 2 external usb 3.0 hard drives

[j77555yta]

I am currently copying a single 100GB file between 2 external hard drives connected to my laptop via USB 3.0. The transfer speed seem to be fluctuating between 30 and 40 MB/s and sometimes going up to 90 MB/s at some periods. What speeds should I be expecting when transferring between 2 external drives via USB 3.0?

 

[kanewolf]

Unknown. If either of the drives is a USB2 device, then you would be limited to about the speeds you are seeing.

 

[jsmithepa]

Speed is limited by the slowest drive of the 2, and by speed I mean a combination of spec + how fragmented is the drive.

I hope u didn't have this grand idea since they use FAST USB3, u expecting USB3 throughput.

 

[USAFRet]

I am currently copying a single 100GB file between 2 external hard drives connected to my laptop via USB 3.0. The transfer speed seem to be fluctuating between 30 and 40 MB/s and sometimes going up to 90 MB/s at some periods. What speeds should I be expecting when transferring between 2 external drives via USB 3.0?

Lots of different factors come into play.
Cache size on either drive.
Fragmentation level.
CPU and OS performance.
Performance of either/both drives.

There is no singular "number".

 

[doraimom]

I have the same question. Even though many factors may affect the speed, a general mean value is reasonable to be expected. I'm using an external 3.0 HD to transfer 1TB to an external SSD 3.1 HD.
But, unexpectedly I'm reading speeds of 5MB/s. After more than 15 hours, I didn't get past 8% of the total transfer.
I don't think those values are reasonable in an "i7" 8th generation laptop with 32GB of RAM. Not even in weaker PCs that would be acceptable I think.
Am I wrong interpreting that something is wrong here? Just bought this SSD disk yesterday,

 

[USAFRet]

I have the same question.

Please start a NEW thread for your particular situation.

But as said in the replies here, what you're seeing is probably not unusual.