I am looking to an an external HD and found 2 models of the same HD...one with both Firewire and USB2 and another UNIT ...exactly the same but with only USB2 for $40 less. Is Firewire faster than USB2?

THANK you!Firewire supports a transfer rate 400-1000 Mbps

USB2 supports a transfer rate of up to 480 Mbps

To need to check the HD specs to see the actual rates they can transfer data as the above are only the potential rates.



Firewire (as in the older Firewire400 standard) is a bit slower than USB2 *in specs* but tends to transfer as fast if not a tad faster than USB2.  Whilst USB2 is theoreticlally CAPABLE of more, it tends to 'burst' up to the higher rate rather than maintaining a steadier throughput like Firewire, and thus tends to be (slightly) slower in practice.

Firewire800 though blows USB2 out of the water.  It's quite a new standard that is available only on top-end hardware (I don't know of any brand name computer that comes with Firewire800 as standard apart from Apple's G5).  With Firewire800 you're much more likely to be limited by the speed of the HDD as Mektek has suggested - you'll need a MIGHTY fast HDD to saturate Firewire800 with data.

Given your choice is more than likely between Firewire400 and USB2, and that their SPEEDS are really very close in practice, I'd be more concerned about compatility and price.  Given USB2 is FAR more common than Firewire (apart from on 1-3 yr old Apple computers), you're probably more likely to be using USB2 - particularly when you take that HDD over to a friend's place (if that is your intention).  Also given the price, I'd be buying the USB2 version unless you have other factors in play.