On Macs we can use a “RAID 0” also known as “Striped Raid” configuration to speed up iMac's data access rates thus dramatically improving overall user performance and OS X performance.

We can remove the Optical Drive from any iMac (2007-2011) models and insert an “Optical Bay Hard Disk Adapter” for a total of 2 Hard Drives, this will allow us to format both drives using Apples built in RAID 0 configuration through Disk Utility.

iMacs capable of “RAID 0” and a list of possible improvements:

Model Year	Model Type	Model Size	SATA Drive Speed	DVD Bay Speed	Standard SSD Test (6Gbs SSD)	RAID Test Results (2 SSD 6Gbs Rate)	Will This Benefit My System?
2007	iMac	20”	3Gbs	1.5Gbs	265MB/s	210MB/s	No Benefit
2008	iMac	20”	3Gbs	1.5Gbs	265MB/s	210MB/s	No Benefit
2009	iMac	20”	3Gbs	1.5Gbs	265MB/s	210MB/s	No Benefit
2007	iMac	24”	3Gbs	1.5Gbs	265MB/s	210MB/s	No Benefit
2008	iMac	24”	3Gbs	1.5Gbs	265MB/s	210MB/s	No Benefit
2009	iMac	24”	3Gbs	1.5Gbs	265MB/s	210MB/s	No Benefit
2009	iMac	21.5”	3Gbs	1.5Gbs	265MB/s	210MB/s	No Benefit
2010	iMac	21.5”	3Gbs	3Gbs	265MB/s	480MB/s	Almost Double File Transfer Seed (Transfer 1GB File in 2 Seconds)
2011	iMac	21.5”	6Gbs	6Gbs	465MB/s	920MB/s	Almost Double File Transfer Seed (Transfer 1GB File in 1 Seconds)
2009	iMac	27”	3Gbs	1.5Gbs	265MB/s	210MB/s	No Benefit
2010	iMac	27”	3Gbs	3Gbs	265MB/s	480MB/s	Almost Double File Transfer Seed (Transfer 1GB File in 2 Seconds)
2011	iMac	27”	6Gbs	6Gbs	465MB/s	920MB/s	Almost Double File Transfer Seed (Transfer 1GB File in 1 Seconds)

More Information on RAID Systems:

RAID stands for, redundant array of independent disks. RAID is a data storage virtualization technology that combines multiple physical disk drive components into a single logical unit for the purposes of data redundancy, performance improvement, or both.

RAID 0 consists of striping, without mirroring or parity. The capacity of a RAID 0 volume is the sum of the capacities of the disks in the set, the same as with a spanned volume. There is no added redundancy for handling disk failures, just as with a spanned volume. Thus, failure of one disk causes the loss of the entire RAID 0 volume, with reduced possibilities of data recovery when compared to a broken spanned volume. Striping distributes the contents of files roughly equally among all disks in the set, which makes concurrent read or write operations on the multiple disks almost inevitable and results in performance improvements. The concurrent operations make the throughput of most read and write operations equal to the throughput of one disk multiplied by the number of disks. Increased throughput is the big benefit of RAID 0 versus spanned volume, at the cost of increased vulnerability to drive failures.

Please note that the test data in the table above was conducted at "Save Apple Dollars" labs is subject to change and results may differ depending on the Hard Drive technology used in other systems.

OS X EL CAPITAN AND YOSEMITE RAID

Open OS X Terminal and use the command bellow instead of GUI Disk Utility:

diskutil appleRAID create stripe Storage JHFS+ disk2 disk3

Copy and paste this command into terminal. Make sure that

disk2

and

disk3

correspond to the disks that you have plugged in through the SATA to usb converter cable!

You can check disk information by typing in:

diskutil list

OS X El Capitan has an updated Disk Utility GUI and RAID has been removed for user safety purpose