Question about write speed for My Book Essential 2TB

I understand that USB 2.0 data transfer rate will be much slower than USB 3.0, but for many people with older systems USB 2.0 is all that is possible.  According to the specifications, the WD My Book Essential 2TB transfers data at 480Mb/s maximum via USB 2.0.

I performed a copy test, transferring 28Gb of files (7,400) from my laptop to the WD My Book Essential 2TB drive.  It took 35 minutes to complete.  That’s more than 1 minute per 1 Gb.  Now, the drive being copied from has a slower data transfer rate at 300Mb/s, but it is also SATA 3Gb/s, 5400rpm, 12ms avg seek time, and 8Mb buffer.

I’ve read that a drive running at 5400rpm with a data transfer rate of 300Mb/s should transfer 1Gb in about 30 seconds.  That means 30Gb should transfer in about 15 minutes.  Based on this, it doesn’t look like my computer’s hard drive is the bottleneck here.  Shouldn’t the WD My Book Essential 2Tb drive be able to transfer 30Gb in 15 minutes, rather than over 30 minutes?


I conducted a different test for comparison purposes.  I copied 275 files comprising 1Gb of data to a Kingston USB drive, a DT-R500 with 20Mbyte/s write speed.  The copy took 2 minutes 10 seconds.  I then copied the same data to the WD My Book 2Tb drive, which took 1 minute 30 seconds.  Now, the WD 2TB has a 480Mbit/s transfer rate.  From what I’ve read, this translates to 60Mbyte/s.  I’ll bet this is the read speed.  But even if we go conservative on that and say the write speed is 300Mb/s, that’s more than twice the speed of the USB drive.  And yet, it was only 40 seconds faster.  That doesn’t seem quite right to me.

Try using the drive on two different computers and see if you have the same results

there should not be any bottle neck that has something to do with the internal drive and the USB controller

The computer is very efficient and there are no bottlenecks that I can detect.  Other computers I have available are much older and running a different operating system, so I don’t think it would be useful to try testing on them.

I do have another hard drive that I just performed a comparison test with.  It’s a LaCie 250Gb 7200rpm USB 2.0 drive, so it should beat the WD drive.  It did, but not by much.  Whereas the WD drive copied the files in 1 minute 30 seconds, the LaCie did it in 1 minute 20 seconds.  That’s close enough for me.

I plan to get a USB 3.0 ExpressCard adapter, so that will open up the data transfer rate a bit more with the WD My Book.  It won’t be as fast as a computer with a motherboard architecture having USB 3.0 built-in, but it should be decent.