Slow external hdd transfers?

I thought usb 2 were suppose to get speeds of 480mb/s. I recently bought a external hdd (500gb 7200rpm) and when i transfer say a dvd thats 4.3gb its speeds are usually like 15mb/s.

How can i make it go faster? Im using the ports on the back of my laptop. The hdd is a seagate freeagent desktop.

http://www.newegg.com/Product/Product.aspx?Item=N82E16822148235

 

That sounds about right. You will never get 480mb/s, not going to happen. I don't think you can do anything to speed up.

 

Its not 480megabytes per second, it is 480 megabits per second. USB has a therorectical maximum transfer speed of 60Megabytes per second. The fastest I have ever seen was the 34megabytes per scond speed of my corsair flash voyager GT.

K-TRON

 

Thanks K-Tron, you clarified something that was not an issue, none of us seemed confused, but thanks for the input. Still short of the 60MB max you mentioned and no help speeding up.

 

My homemade external harddrive with its 1tb hitachi drive in it has a sustained data transfer of 32mb/sec. Tested with HDTUNE. The drive is clearly faster, it may just be the sata to usb converter which is bottlenecking the transfer. I have a smart gear usb to sata converter with JBOD SATA 2 support. It is most likely the converter which is slowing down the transfer rates. Like anything if you think of it on a bit rate level, 32mb.sec is still a remarkable amount of data which flows through those chips.

K-TRON

 

OK I might of made a mistake! I can't believe it, I know all the rest of you can't either! Alright, a 15 MB transfer rate on a USB connection is good, 15mb is not. So what are we dealing with? let us know.

 

I use Seagate 7200.11 500GB with USB (HP notebook) and it gives me 20-25 MiB/s, when copying between this disk and internal Hitachi 7k200, depends of disk area and partition. Transfer tested with HD-Tach... I don't remeber, some 5X MiB/s. I don't know which one is slower (OK, internal one is slower if connected via the same interface, external one is slower in this particular scenario). I consider that a maximum you can get thru USB 2.0. Usually it would be like yours 15 MiB/s, more or less.

When copying something from fast external DVD I get max. 15-20 MiB/s.

Now, USB2 rated speed is 480 Mbps which is exactly 60 MiB/s, or 60 megabytes per second if you like. But there is some substantial overhead, which slows data transfer (basically control functions, which are CPU dependent and not realized by USB hardware) and results also with slower sustained data rate. This is why slower rated firewire (400 Mbps) can achieve slightly higher actual speeds, it has no such overhead. So, you cannot expect true data transfer to be quicker than some 55 MiB/s even in a perfect scenario.