USB3.0 transfer faster than internal SATA III?

[teckneeculler]

Background:
Just bought myself a new Welland USB3 2xslot hdd dock. It's connected to my 2-year old W7 PC via one of the computer's two USB3 ports (actually, the front one).

My PC's main HDD is a 2-year old 2TB Sata3. It's about half full. (My CPU's an i5, 16GB ram)

Oddity:
I've just copied a bunch of data from my PC to a 2009 Sata2 HDD in the Welland USB3 dock. The transfer rate was between 90-100 MB/s.

Shortly after, I made a copy of a 20GB folder (that is, duplicated it) on my main 2TB Sata3 HDD. The copy transfer rate was about 45MB\s.

I'm surprised, to put it mildly. If anyone had told me that a USB external data transfer could be twice as fast as an internal transfer on the same drive, I would have been skeptical.

Comments anyone?

 

[townsbg]

According to Wikipedia the max speed for USB 3 is 5 gbps where as sata 3 the max speed is 6 so they are close.
USB 3.0 - Wikipedia
Serial ATA - Wikipedia

 

[essenbe]

Internal sata is much faster than USB 3.0. The figures quoted are under ideal lab conditions. You will never see anything close to 6 Gb/s in real life. This may help.

 

[Bat 1]

Reading and Writing on the SAME drive will always be significantly slower than transferring from one drive to a second one.

 

[essenbe]

Reading and Writing on the SAME drive will always be significantly slower than transferring from one drive to a second one.

I'm not sure I understand what your point is, but there are quite a few threads on this forum about which is faster USB 3.0 or Sata. Sata is always faster. I use both and there are a lot of factors involved that can speed up or slow down copy/transfer speed. But in every case in every thread sata has always been faster.

 

[Bat 1]

I'm not sure I understand what your point is, but there are quite a few threads on this forum about which is faster USB 3.0 or Sata. Sata is always faster. I use both and there are a lot of factors involved that can speed up or slow down copy/transfer speed. But in every case in every thread sata has always been faster.

From The OP:

Oddity:
I've just copied a bunch of data from my PC to a 2009 Sata2 HDD in the Welland USB3 dock. The transfer rate was between 90-100 MB/s.

Shortly after, I made a copy of a 20GB folder (that is, duplicated it) on my main 2TB Sata3 HDD. The copy transfer rate was about 45MB\s.


Comments anyone?

Shouldn't be hard to understand ?

 

[SIW2]

Shortly after, I made a copy of a 20GB folder (that is, duplicated it) on my main 2TB Sata3 HDD. The copy transfer rate was about 45MB\s.

Reading and writing on same disk.
bat1 is correct.

 

[Layback Bear]

My understanding is.

When reading from one drive and writing to another drive is faster because each drive is doing just one thing.
One drive is writing and the other drive is reading.

If one is reading and writing using the same drive that drive is actually doing two things (reading and writing).

Please don't ask me to prove it.

Jack

 

[Bat 1]

Please don't ask me to prove it.

Initial Burst was 180MB/s on both tries but speed dropped within seconds.
From SSD C: to SSD D: in My Laptop

From Desktop to Desktop