Western Digital My Book Essential Edition WDH1U6400 640 GB

...is too slow for you, western digital do offer firewire ports which can up to 3,200 Mbit/s Max.
The unit itself is a bit bulky but personally i like the design as it looks quite good if it is sat on the desk or on top of the machine.
Installation was pretty simple aswell - another plug and play unit or if you wanted to use it to back up files from your machine there is software provided to other you this option.  ... more

I purchased this external hard drive about 2 years ago for roughly £90. Since then I've used it to save large video files which has been great since it doesn't slow down my main hard drive to clog it up. Its helped make my pc run faster however it does take a longer time for my pc to boot up.
A couple of things about the specs are:
Serial Bus Transfer Rate (USB 2.0) 480 Mbits/s (Max)
Requires a seperate power supply 100-240 VAC
A few things to note about hard drive is the estimations are never accurate. Although its a 750gb, when they are formatted they actually only store 698gb on a FAT 32. This leads me on to a second point which is FAT 32 limits file size to 4gb. But in most cases this shouldn't be too much of an issue. But if it is you can always reformat the hard drive to NTFS which will resolve the problem.
This has been a fantastic device, has never failed to boot and loads applications very smoothly if you wished to save internal HD space. however if USB 2 is too slow for you, western digital do offer firewire ports which can up to 3,200 Mbit/s Max.
The unit itself is a bit bulky but personally i like the design as it looks quite good if it is sat on the desk or on top of the machine.
Installation was pretty simple aswell - another plug and play unit or if you wanted to use it to back up files from your machine there is software provided to other you this option. 

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