How many pins on my 400 firewire on the back of my iMac, see iMac specs below. I can count 6 copper bands on my new Maxtor external drive but can't really see what to count on the iMac.....
If your external hard drive has a 9 pin connection it WON'T run @ 800 mps rate it'll run @ 400 mps because the iMac has a Firewire 400 aka 1394a port..
To get 800 mps rate you need a firewire 800 card aka 1394b card and cable, external case thats capable of that transfer speed..