If the inside of your Mac is no more mysterious to you than the inside of your sock drawer, an internal hardware RAID (Redundant Array of Independent Disks) array may be the perfect way to add lots of very fast storage to your system or to upgrade your boot drive. And because two bare ATA hard drives are often much less expensive than one external FireWire or SCSI drive with twice the capacity, it makes sense to look into this option. Storage this fast is well suited to editing DV video, accessing large graphics files, or serving up Web pages. An internal array also prevents the clutter of external drives and their cables.

Our Willing Subjects

We tested four ATA PCI RAID cards that combine two ATA drives to create one large, fast volume using the latest, 133- MBps version of ATA: Acard's AEC-6880M/ATA-133 RAID, Miglia's Alchemy ATA 133 RAID PCI, SIIG's UltraATA 133/100 RAID, and Sonnet Technologies' Tempo RAID133.

Each PCI card employs hardware made by Acard, which also sells its own card. As a result, the four cards looked and behaved exactly the same--the choice you make will come down to price, the quality of the card's manual and technical support, and the length of its warranty.

Give RAID a Chance

These cards provide the easiest RAID configuration the Mac has ever seen. You simply use an ATA cable to connect an ATA drive to a port on the PCI card, use another ATA cable to connect a second ATA drive to the next port on the card, flip a switch on the card, and reboot. The PCI card then reports to the CPU that the drives are a single SCSI device and that they appear as one volume on your desktop. You can then use any Mac drive-formatting software that works with SCSI drives--including OS 9's Drive Setup and OS X's Disk Utility--to format the RAID array.

The PCI cards accomplish this feat by using RAID Level 0, which alternates the data stream between two or more drives. Since both drives can write data at the same time, a two-drive array has the potential to be twice as fast as a single drive. When we tested this theory, the speed improvements of using a single drive were closer to 25 percent than 100 percent, but we were able to capture uncompressed video to our array at 27 MBps, which we were not able to do with a single drive. However, the catch with RAID arrays is that if either drive fails, you lose the data on both drives.

In a Dead Heat

Because all of these products use the same hardware, it's not surprising they turned in nearly identical performance results in our tests. The hardware RAID configurations of two 80GB drives were faster than a single 80GB drive by as much as 25 percent. The only exception was the Adobe Photoshop Save test, in which a single drive was slightly faster.

For comparison, we also switched the RAID card to Normal mode and used Mac OS X's Disk Utility to create a software array with the same drives (see "Advanced RAID"). In our Finder File Duplicate test, the software-based RAID was 60 percent slower than the hardware RAID and 30 percent slower than a single drive. This is because a software RAID array relies on the CPU to send a quick series of commands alternating between two drives. SCSI and FireWire software RAIDs also experience a slowdown, but unlike ATA, these technologies better handle concurrent data, softening the performance hit to a system. As a result, SCSI and FireWire software RAIDs tend to perform faster than a single drive but slower than a hardware RAID.

If you plan on adding a single drive to your desktop Mac, you don't need to invest in an ATA PCI card at all--you can connect an additional drive to the ATA/66 internal bus that ships with modern Macs. We tested this configuration against the ATA/133 bus on the PCI cards, using Barracuda 80GB Ultra ATA/100 drives, from Seagate. To see whether the ATA/133 bus on the cards was faster than the ATA/66 bus built into current Power Macs, we configured our test drive as a slave and moved it to the Mac's internal bus, where the boot drive was also located. This configuration performed identically to the 80GB drive attached to the PCI cards. Not surprisingly, our single drive transferred data at no faster than 66 MBps.

Quality of Manuals

Each ATA PCI RAID card we tested included a useful manual with instructions on how to install and configure the card. The documentation also covered initializing the drives in both OS 9 and OS X.

However, the hardest part of setting up an internal array is physically installing the internal drives in your computer. Miglia and Sonnet do a good job of explaining how to configure a drive as a master or slave with jumpers. The Acard and Sonnet manuals have useful and clear diagrams showing how to attach the master drive to the end of the ATA cable. Because using an ATA card is an economical way to replace an older SCSI drive, Miglia goes so far as to include illustrations on how to install a single drive in a range of pre-G3 Power Macs, beige G3s, and blue-and-white G3s. Miglia also includes instructions in French, Spanish, Italian, and German.

The Acard Web site has a list of supported drives from Seagate, Quantum, Maxtor, Fujitsu, IBM and Western Digital. These are the drives Acard has tested, but these are not necessarily the only drives that will work with the cards. Both Sonnet and SIIG confirm that they have been able to use the card with a variety of drives, including ATA/133 drives and older ATA/33 drives.

Technical Support

Each vendor hopes to differentiate itself by providing superior technical support. Although Acard's only office is in Taiwan, they contract with Mars Technologies in the United States ( for their technical support. We were able to get through to a technician within five minutes. And in less than ten minutes, Sonnet's phone support was able to answer our simple question about the number of drives you can add to the card.

SIIG and Miglia provide e-mail support for their products, and although both vendors were able to answer our question, e-mail support isn't much help if your new PCI card seems to have crashed your system. SIIG has a technical-support phone number, but it's not toll-free, and it's not listed in the documentation or on the company's Web site. SIIG took a whopping six hours to respond to our e-mail. Miglia has a technical-support number, but it's an international call (to England); however, the company sent a very thorough answer to our e-mail question in an hour and a half.

Macworld's Buying Advice

If you don't mind pulling out a screwdriver and installing the hardware yourself, an ATA RAID card is a fabulous way to add excellent storage capabilities to your Power Mac. We recommend the SIIG card because of its low price and longer warranty, even though it didn't have the best documentation or tech support in the roundup. If you're a RAID novice, you may be better off with the manual and tech support provided by Sonnet, or you can simply avoid the headache altogether by purchasing an external FireWire drive, though it will be more expensive. As for performance, any one of these ATA PCI RAID cards will provide fast, economical, and clutter-free storage.

Advanced RAID

If you're looking to get into RAID, here's some further information you might find helpful.

Software or Hardware RAID?

Anyone who wants to create a RAID array should know that there are two methods: using the hardware configuration the ATA PCI RAID cards provide, or using RAID software, such as SoftRAID's SoftRAID, Intech's Hard Disk SpeedTools, or Apple's Disk Utility in Mac OS X. In a hardware RAID, the data moves in a single stream from the CPU to the PCI card, which splits the data into alternating stripes. In a software array, the software splits the data stream, and the CPU alternates data traveling to and from the individual drives. Although hardware RAID cards are more expensive than software RAID packages, they are often faster, because a software array taxes your CPU much more heavily. Another advantage of a hardware array is that you can boot your system from it. We were able to boot both OS 9 and OS X from each of our hardware arrays.

Advanced RAID: Two Arrays Are Not Twice as Good

If one array isn't enough, you can attach another two drives to the other port on the PCI RAID card and create another hardware array. To make this work, you have to identify one of the two-drive arrays as the master and one as the slave. You must first set the jumpers, which are about the size of a grain of rice and fit over the pins on the drive (they're usually found between the drive's power plug and the ATA connector on the drive)--we recommend using tweezers.

Although you can connect two master drives and two slave drives to the cards to create two RAID Level 0 arrays, the addition of the slave array will negatively affect performance. The fastest configuration is two master drives of the same size and speed. If you use two drives of different capacities, your array will be only twice the size of the smaller drive.

Waiting for the Bus

If you currently have a drive connected to your Mac's original internal bus, it will not automatically mount on your desktop if you reconnect the drive to the ATA/133 RAID card. To remedy this, you can update the ATA drive's drivers with a formatting package such as FWB Software's Hard Disk ToolKit or Intech's Hard Disk SpeedTools. You can also make the drive visible by reinitializing the hard drive, but any data on the drive will be wiped out. Drives formatted with Mac OS X's Disk Utility can be moved from the internal ATA bus to the ATA card without this problem.

Getting Back to Normal

For troubleshooting your RAID array of drives, there is a small switch on the PCI card that lets the two drives operate in Normal mode, so the individual drives appear as themselves, letting you scan or repair them independently of one another with a disk utility but not retrieve data or boot from the drives. If you plan to use the drives separately on an ongoing basis, you'll want an ATA/133 card that does not have RAID capabilities: each company featured in this review also sells less expensive non-RAID ATA cards.

ATA/133 RAID Cards Compared

* = Editors' Choice.

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