I have one of your eSATA burly boxes from way back. Right now they hold back up volumes. Meanwhile in the Mac Pro 2009, 2 bays are devoted to 250GB each scratch raid zero. I would like to switch this arrangement so I wonder if I lose any measurable speed to scratch raid zero thru the eSATA hookup instead?
Thanks for any advice !!

I have early 2009 (Nahelem?) Mac 2x2.26 quad core xeon
NVIDIA GeForce GT 120 512 MB