USB 2.0 actual transfer speeds

[chaslinux]

I have a large amount of files I want to transfer from one USB 2.0 device to another. I started transfer and found it transferring quite slow, around 8.5MB/s. I thought USB 2.0 had a theoretical limit of around 480MB/s. Practically, I expected around 30MB/s. I'm quite sure I've had 30MB/s going from a USB key to a hard drive, but in this case I'm going from a USB 2.0 external drive to another USB 2.0 external drive through my Dell Netbook (which has USB 2 ports). I'm thinking maybe one of the cables is only USB 1.1?

[Indigo]

You're confusing your MBs and Mbs.

USB 2.0 is 480 Mb/sec. Megabits. That translates out to about 60MB/sec for the entire chain (if you use more than one USB device, you cut that amount down accordingly, and since you're saying two USB 2.0 devices, that's not unrealistic to expect that kind of cut that you're experiencing)

USB cables also, for the most part, don't care about the USB spec. I've used old printer cords from 5 years ago with USB 3.0 ports and it still worked at USB 3.0 speeds. They just changed the signaling of the standard, not so much the physical aspect, which is why you can use USB 3.0 on USB 2.0 and 1.1 ports.

8.5MB/sec is actually average for what you are doing, and depending on what you're transferring, the speed can rise and fall accordingly. When it does lots of little files, it can show a "slow" speed like 8.5MB/sec, and when it's doing large files, that number may go up as it has time to estimate the true speed.

I wouldn't read too much into it.

[EchoNatek]

yeah transfer rate really is a bitch ^-^
there is plenty of transfer rates to remember.

Nice post from Indigo. i really miss the reputation button -.-
Indigo +1 rep