New 2TB My Studio LX HD slowing my imac way down

I just bought a 2TB Studio LX external HD from the Mac store in fact. Ever since I started using it last week my imac is almost not usable its so slow. Almost every time I try to even move my mouse or click on something I get the pinwheel. I turned it off and things seem to be much better. Not sure why this would be as there are only about 600gb of files on it so far and Im using my firewire port. Ive ran my disk utility and done a disk repair and have used Onyx to try what I could think of. I even removed istat pro and symantec but the thing that helped the most was just turning the hd off. How can I use this new HD while still getting my imac to work?
Thanks

ak6143 said:

I even removed istat pro and symantec but the thing that helped the most was just turning the hd off. How can I use this new HD while still getting my imac to work?
Thanks

Click to expand...

I suspect that's your problem right there. Are you sure it's completely gone? Symantec goes pretty deep and it's known to be horribly difficult to remove.

Quite honestly, the cure is worse than the (non-existent) disease in the case of Symantec.

Also, I would disable Spotlight indexing on the external. Open System Preferences => Spotlight. Click the Privacy tab and then drag the external's icon into the list. See if that makes a difference.

Im not 100% sure I got Symantec off all the way or that I know how but I did that part 2 days ago and it was still terrible trying to use the computer but when I shut the HD off this morning its been working great. Ill try changing that preference but if there are any other suggestions Im certainly greatful.