I have tested the USB transfer rate of the playbook and compared it to an external hard disk
File used: avi file
Size: 550 MB
Playbook :1mn 56"
External hard drive (Fujitsu) : 0mn 22"
USB flash drive: 1mn 25"
Why the playbook transfer rate is so slow ?
That's like comparing apples to oranges. Hard drives typically spin at 7200 RPM and Serial ATA have transfer rates of 150-300MB/s. Like any flash memory transfer rates are always way lower (just like a USB stick). The PB connected via USB averages out to around 5MBps..
Nothing to do with the PB itself.
Updated the test by adding a USB flash drive