The MAXPower eSATA 6G offers excellent value; with two eSATA ports, you can hook up two external enclosures: two external hard drives, two 4-drive QX2 enclosures, a Voyager Q Drive Dock and a hard drive, or any combination thereof. All for a rock-bottom price of about $59!
Reasons to use an eSATA card
It's all about performance. If you have 500GB or 1TB of data to backup, this can take many hours using Firewire 800. Or if you want fast external storage for video or other performance needs (like a Photoshop scratch volume), or a RAID 0 stripe, eSATA is your only performance option.
Today's fast hard drives run at up to 130MB/sec, whereas aging Firewire 800 trudges along at ~83MB/sec in the ideal scenario, but often much slower, especially for writes. An enclosure like the OWC QX2 offers about 250MB/sec. In short, eSATA yields something like 1.5 - 3X the performance of Firewire 800 for transferring or working with large files.
Driver software, 64-bit mode
An added plus of the 6G is that it needs no driver software: just install and go!
Driver software for eSATA cards has caused me a lot of headaches over the years (crashes or sleep problems under certain conditions), so omitting it is a huge plus.
I tested the 6G in my Mac Pro Nehalem booted into the 64-bit Snow Leopard kernel, and it ran perfectly.
Benefits of eSATA 6
While few external enclosures support eSATA 6 as of early 2010, even fewer benefit from it: eSATA 3 is plenty fast for single or dual-drive hard drive enclosures.
However, that will change rapidly in 2010. Units that have three or more drives accessed via one cable (QX2) should see substantial performance gains.
Enclosures that are port multiplied (PM) will also see great benefits with eSATA 6, but the MAXPower eSATA 6G card does not support PM. If you need PM, consider the Firmtek SeriTek/4ME4-E.
But the most interesting trend is that of solid state drives (SSD). A single SSD can offer performance up to 260MB/sec, which totally saturates the bandwidth of an eSATA 3 cable.
Thus eSATA 6 comes to the rescue, allowing two SSD drives to run at nearly full speed over a single eSATA 6 cable (at least in theory, specific products might have limitations). It also makes possible future single SSD drives to offer performance in the 500MB/sec range.
Form factor, power usage, etc
The MAXPower eSATA 6G is tiny as PCIe cards go.
Its neat-and-clean layout suggests good design and reliability, as well as low power draw. Installation is the same as with any PCIe card: pop the cover, insert the card into an available slot, reboot.
As no eSATA 6G enclosure was available, I was not able to verify the 6G compatibility.
I tested with my FirmTek SeriTek 2EN2 dual-bay enclosure, and the NewerTech Voyager Q.
I tried unmounting the volume, powering the drive off, then powering it back on (this can sometimes fail with certain eSATA cards). I experienced no problems at all. Fantastic!
The MAXPower eSATA 6G is a single-lane card offering bandwidth of 500MB/sec (in theory) with recent Mac Pro models. Actual speed depends on the drives used: a pair of hard drives can use only about 250MB/sec. So the 6G is more than capable of handling the needs of a vast majority of users.
Real-world performance depends on the drive mechanism, the computer model, and how programs actually read files from disk. And in the real world, performance often falls at least a little short of the theoretical.
Performance shown below means sustained transfer rate, which is the most important factor for many usage scenarios. (When many thousands of small files are involved, speed is lower, due to system overhead).
For this comparison, the Firmtek SeriTek/4ME4-E was used, a card I use regularly.
With a single drive, speed is almost identical to the Firmtek SeriTek/4ME4-E.
In the real world, this means identical.
Two-drive RAID-0 stripe
The MAXPower eSATA 6G delivers identical read performance to the FirmTek SeriTek/2ME4E, a considerably more expensive card.
For writes, the SeriTek/2ME4E delivers better performance. The reason for the discrepency is unclar, but the results were very consistent with repeated testing.
For this test, I used a pair of Hitachi 7K2000 2TB hard drives capable of ~126MB/sec each. A pair of them in a RAID-0 stripe should yield performance of ~250MB/sec, but of course speed of the drives themselves drops as they fill up, so that's a best-possible figure.
The test "mule" was my 2009 2.66GHz Mac Pro Nehalem with 12GB memory and Mac OS X Snow Leopard 10.6.2. The two Hitachi drives were installed in the FirmTek SeriTek/2EN2, a dual-bay enclosure with two eSATA 3 cables, one to each drive.
At about $59, the MAXPower eSATA 6G PCIe card offers outstanding value for anyone looking to approach eSATA. While it has two ports, that is plenty for most users, and more than one card can be installed to extend the number of ports, and bandwidth.