Taken from : //www.macnn.com/reviews/owc-mercury-electra-6g-240gb-ssd.html

OWC Mercury Electra 6G 240GB SSD

August 23rd, 2011
OWC Electra 6G aims to balance speed and affordability

Over the past several years, we have watched many companies release solid-state drives (SSDs) with outstanding performance but prohibitive price tags. Although SSDs still do not compare to traditional hard drives in terms of gigabytes per dollar, the price of SSDs has continued to drop as the speed and reliability continues to climb. Other World Computing has expanded its Mercury lineup with the Electra 6G, a new SSD that takes advantage of SATA 3.0 hardware found in the latest Macs. In our full review, we try out a 240GB Electra 6G built with a 2.5-inch form that serves as an upgrade for notebook HDDs. Build quality and installation

Replacing the stock 2.5-inch hard drive in a MacBook Pro is a straightforward process; the SSD fits comfortably in the bay. We were able to swap the drive and begin a fresh Mac OS X Snow Leopard install in just a few minutes. The SSD can be easily configured and formatted in the same way as a traditional disk drive.

OWC houses the NAND flash chips in an attractive aluminum housing with a blue anodized finish. The drive is quickly buried in the computer out of sight, however the build and finish are nice touches that speak of quality.


The Electra 6G serves as one of OWC's high-end SSDs, second only to the Extreme Pro 6G. The latter model brings a boost in performance, alongside a slightly higher price tag. The Electra is nonetheless claimed to reach respective transfer rates of 556MB/s and 523MB/s when reading and writing compressible data. Although the Electra falls with 4MB/s of the Extreme Pro 6G when dealing with compressible data, the top-end SSD is claimed to read incompressible data more than twice as fast. The less expensive option is said to achieve respective transfer rates of 208MB/s and 235MB/s when reading and writing incompressible data.

Many drives are currently configured to take advantage of SATA 2.0 interfaces, which are rated at a maximum speed of 3.0 Gigabits per second. The Electra '6G' designation for the Electra and Pro variants presumably highlights support for SATA 3.0, the latest standard, which ups the maximum data transfer speed to 6.0 Gigabits per second.

Although only the latest notebooks support SATA 3.0, we still observed a significant difference in transfer speeds between OWC's Electra and Pro models when testing the SSDs on a 2009 MacBook Pro limited to SATA 2.0. Nonetheless, we were unable to achieve OWC's advertised results without connecting the drives via SATA 3.0. In the MacBook realm, the only offerings that support SATA 3.0 include 2011 MacBook Pros. Unfortunately, users will be unable to upgrade their notebooks to support the fastest standard, unlike adding USB 3.0 ports via ExpressCard adapters.

When tested using Xbench, the Electra scored an average of 211 on the benchmark utility's overall scale. The SSD achieved read and write speeds near or over 100 MB/s for most of the sequential tests, while random operations mostly ranged from 70 MB/s to 110 MB/s. The SSD was much faster than a 5400rpm disk drive in seven out of eight tests, usually by a significant margin. The only comparable performance was observed when running sequential read operations using 4K blocks. Compared to the Electra's 211 score, the stock Toshiba disk drive only managed to reach a score of 40.

Switching to Windows XP via Boot Camp showed similar results from ATTO's disk benchmarking utility. The Electra reached just over 100 MB/s reading data, while write operations fell closer to 120 MB/s. The stock hard drive struggled to surpass 25 MB/s, though a clean install likely would have pushed the numbers past 40 MB/s to 50 MB/s.

We expected the 2009 MacBook Pro's SATA 2.0 interface to work as a bottleneck and potentially eliminate any performance difference between the Electra and the Pro variants, however the benchmarks showed a considerable gap in performance. Compared to the Electra's 211 Xbench average and 100 MB/s pace in ATTO, the Pro averaged 315 points in Xbench and surpassed 200 MB/s in Boot Camp.

Aside from the benchmark numbers, we experienced a noticeable speed boost in real-world situations. Mac OS X and Windows operating systems both booted much faster, while complex software also loaded without requiring the patience that a HDD sometimes necessitates.

Final thoughts

Now that SSDs with usable capacities no longer cost more than the computers to which they are connected, drives such as OWC's Electra 6G have become more of a practical storage choice. Users without the need for SATA 3.0 transfer speeds may still be inclined to spend around $100 for a spacious 1TB disk that fits inside a notebook, rather than paying $450 for the 240GB Electra 6G. But for those who regularly utilize data-intensive software for functions such as video or photo editing and gaming, the additional money may prove well spent. One of the Electra's closest competitors happens to be OWC's Extreme Pro 6G, which squeezes SATA 3.0 to the max for $550 in 240GB capacity.

-Fast, configured for SATA 3.0

-Easy to install

-Three year warranty

-Still considerably more expensive than HDD

-Slightly slower than Extreme Pro 6G