Hard Drive Data Transfer Speed- Which is Faster - Internal HD or External Firewire?

[sblake]

I have a 7200RPM ATA 100 HD that I'm going to use either as a second drive for data stotage and backup or put it in an external firewire case. Which will transfer data the fastest and approximately how many MB's per second could I expect from each. It seems that none of these can actually achieve speeds indicted in the specs. Very confusing to me.

 

[Pariah]

IDE will, though firewire is more convenient as a backup solution. Speed shouldn't really be much of an issue for backup storage unless you are backing up GB's of data every day.