Sign in with
Sign up | Sign in
Your question

Transfer speeds

Tags:
  • Hard Drives
  • External Hard Drive
  • Storage
Last response: in Storage
Share
January 15, 2011 4:49:40 PM

Hi, when I transfer data from a partition on my HDD to or from my External HDD I usually see speeds of betewwn 15 and 23MB/sec. I have it connected via usb 2.0. My machine is a Core i7 with 9GB ram and a 7200rpm HDD. Does that seem really slow? Isn't USB 2.0 480MB/s? or is it 48Mb/s? Any input would be appreciated.

More about : transfer speeds

a b G Storage
January 15, 2011 10:10:09 PM

USB max transfer is 480Mbps (mega bits per second) and not 480MB/sec (megabytes per second). So in bytes that would be max of 60MB/sec.

The transfer is NOT continuous at 480Mbps, but in pulses as in sine wave. So the average transfer rate is way below 480Mbps. The catch is UP TO 480Mbps. Something that USB proponents don't make it clear.

If you are transfering a large file (hunderds of MB) the process will take some time. So the speed you notice is normal.

Firewire (1394a) is even better than USB since the transfer is constant 400Mbps.
m
0
l
January 16, 2011 1:59:15 AM

Wow! Great answer. Thank you.

Thoughts on eSATA? I have to do some testing and storage organization and I may need to buy a new external storage device. I have seen 2TB eSATA devices for short $.
m
0
l
Related resources
a c 415 G Storage
January 16, 2011 3:48:20 AM

15 to 23MByte/sec is slow even for USB 2.0. I normally see transfer rates of about 30MByte/sec up to about 35MByte/sec. If you have some bottleneck that's preventing you from reaching the full potential of USB 2.0 then a faster connection such as USB 3.0 or eSATA may not help.

What are the sizes of the internal and external hard drives that you're transferring between? Older (smaller) drives may not have a very high maximum transfer rate, particularly if the files are near the end of the disk, and the transfer will be bottlenecked by whichever drive is slower.

Are you transferring a few very large files or a lot of smaller files? Lots of smaller files will require more head movement to create directory entries and will probably slow down the maximum transfer rates.
m
0
l
a b G Storage
January 16, 2011 4:59:14 AM

eSATA is much better at 3Gbps, I believe.

USB 3.0 also good but still transfer in pulses at 5Gbps peak!
m
0
l
January 16, 2011 1:36:20 PM

Both drives are 1TB and are fairly new. The files are typically 4.5GB in size. USB 3.0 is not a viable option because I do not have a USB 3.0 MOBO.
m
0
l
!