# How fast is USB 2.0 transfer rate?



## TaiDinh

I just got a 320GB SimpleTech EXHDD: 7200RPM with 8MB of cache.

I am transferring 90GB of data at once to it and it is doing 25.6MB/sec. Is this rate of speed normal? Taking 40 minutes total to transfer everything.


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## Manyak

Quote:


Originally Posted by *TaiDinh* 
I just got a 320GB SimpleTech EXHDD: 7200RPM with 8MB of cache.

I am transferring 90GB of data at once to it and it is doing 25.6MB/sec. Is this rate of speed normal? Taking 40 minutes total to transfer everything.

Max USB 2.0 connection speed = 480Mbps = ~48MB/s

But yeah USB hard drives are slow. The USB controller has to wait for the drive to say "ok ready" before it sends any data, which means waiting for every few bytes to be written.

If you have the option to, hook it up on firewire or eSATA. It will be faster.


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## shinji2k

480Mbps = 60MB/s

But yes, ~25MB/s is what you should be seeing.


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## Manyak

Quote:


Originally Posted by *shinji2k* 
480Mbps = 60MB/s

.....oops


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## TaiDinh

Sounds good. I was worring that it might have been slow. And nope, I'm not able to use firewire or eSATA.









So far, the EXHDD is pretty good. Pretty quiet, but it is big. ><" Oh well, I need the space.

Thanks all.


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## shinji2k

Hehe, it's ok







. Manyak is correct about there being a lot of overhead, taking a good chunk out of the theoretical max transfer rate. eSata is nice to have but does require a new enclosure.


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