On 26 Nov, 2006, at 10:39, Jim Robertson wrote: Are there any of these drives that I cannot physically put into my Dual G5? Will I have to reformat the drive to put it into my Mac Pro once I get it? As far as I can tell from your posting, you have begun to reach the limit of storage on your present drives. I would wonder how much of that data is absolutely necessary and what part of it could be removed without causing severe loss to you. My first recommendation is to consider buying a terrifically large hard drive in an external case, something around 500Gb, for storing all the extra files that you seem to have accumulated in your original and extra drives already. If that isn't practical, then consider making DVD copies of your data and only inserting the disc that has the data that you need for that instance. This would require you to create a library list of data/ disc to be able to locate the proper disc. Other than those suggestions, I really don't have working ideas for such a problem as yours. If you buy a new drive, it will normally be formatted for PC use from the factory. It's a built-in bias that we have to suffer with because of blind prejudice. Therefore, you WILL have to reformat it to be recognized by the G5. As to which drives will fit, I think that as long as they are SATA and measure no more than the available space in your G5 chassis, there should be no problem.