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OCZ's Arc 100 solid-state drive reviewed

A new budget contender

The steady decline in SSD prices has been one of the most fascinating trends of the past few years. Shrinking flash fabrication technologies deserve the bulk of the credit for lowering the cost per gigabyte. However, OCZ also played a role by aggressively discounting its SSDs, which fueled a price war that hasn't fully subsided since.

Those discounts surely contributed to OCZ's former financial difficulties. The company filed for bankruptcy last year, and it was subsequently acquired by Toshiba. All things considered, that's probably the best thing that could have happened. Toshiba is one of the biggest flash manufacturers in the world, and OCZ now has preferred access to the latest and greatest NAND—probably with family discount.

OCZ is making the most of that access with its new Arc 100 SSD. This drive, based on the Barefoot controller, uses the most recent "A19" revision of Toshiba's 19-nm NAND. It's also eminently affordable, with the 240GB and 480GB flavors priced at just $0.50 per gig.

Despite its budget focus, the Arc 100 is supposed to deliver especially strong performance with more demanding and sustained workloads. More importantly, perhaps, there's evidence that OCZ's reliability track record has improved since the firm was purchased by Toshiba. This thing deserves a closer look.

Another Barefoot remix
OCZ's proprietary Barefoot 3 controller sits inside the Arc 100. That chip has dual cores; one is an off-the-shelf ARM Cortex unit, while the other is an "Aragon" co-processor designed by OCZ. The controller is fairly conventional otherwise, with eight parallel NAND channels and a 6Gbps Serial ATA host interface.

We first saw the Barefoot 3 in OCZ's Vector SSD way back in 2012. A slower "M10" revision of the controller powered last year's Vertex 450 and its successor, the Vertex 460. The Arc 100 also uses the M10 chip, but the clock frequency has been dialed back 15% versus the implementation in the Vertex 460.

On the encryption front, the controller can scramble data in hardware using a 256-bit AES algorithm. However, support for the related IEEE and TCG Opal specifications is missing from the Arc 100's feature list, which rules out compliance with Microsoft's eDrive standard and third-party encryption management software. That's a bummer for corporate users, but the omission probably won't bother typical consumers.

The NAND is two-bit MLC stock built on the second generation of Toshiba's 19-nm fabrication process. These A19 chips have narrower dies than their predecessors, allowing more of them to be packed onto each silicon wafer. Toshiba has been using A19 NAND in its own SSDs since earlier this year, and now OCZ is getting in on the action.

All the members of the Arc 100 family employ 8GB flash dies. Most controllers require at least 32 dies to hit top speed, so the 120GB version of the Arc has slightly lower performance specifications than its larger siblings. Here's how the line stacks up:

Capacity Die config Max sequential (MB/s) Max 4KB random (IOps) Sustained
4KB write IOps
Price $/GB
Read Write Read Write
120GB 16 x 8GB 475 395 75,000 80,000 12,000 $74.99 $0.63
240GB 32 x 8GB 480 430 75,000 80,000 18,000 $119.99 $0.50
480GB 64 x 8GB 490 450 75,000 80,000 20,000 $239.99 $0.50

The runt of the family doesn't suffer as much as one might expect. There's only a slight reduction in sequential speeds, and the peak random I/O rates are the same regardless of the capacity. However, the 120GB unit takes a big hit in sustained random write performance. That metric may be influenced more by the amount of overprovisioned spare area than by the number of parallel NAND dies. All the drives allocate the same percentage of their total flash capacity to overprovisioned area that can be used by the controller to accelerate write performance. Since the higher-capacity variants have more capacity to start, the end up with more "spare area" for the controller.

In any case, the 120GB version has a higher cost per gig than the others. You may want to avoid it on that basis alone.

Like a lot of consumer-grade SSDs, the Arc 100 is rated for 20GB of writes per day for the length of its three-year warranty. That works out to 22TB in total, which should be plenty of headroom for most client workloads. You can probably write a lot more to the drive, too. The results of our ongoing endurance experiment suggest that modern SSDs can write hundreds of terabytes without issue.

In an interesting twist, the Arc 100 comes with a new ShieldPlus warranty that's supposed to simplify the return process. If users encounter problems with their drives, they need only provide the serial number—no proof of purchase is necessary. OCZ's support reps will try to rectify the problem remotely, and if they can't, they'll ship out an advance replacement unit with a pre-paid return label in the box. The ShieldPlus warranty will initially be offered only in North America and the EMEA region (Europe, the Middle East, and Africa), but its scope will expand to other regions in the future.

We can't discuss warranty coverage without mentioning OCZ's somewhat checkered reliability track record. Much of that is well in the past, but even the user reviews for some of the company's earlier Barefoot 3-based drives are filled with complaints about DOA units and premature failures. Happily, though, the tide appears to be turning. The Amazon and Newegg user reviews for OCZ's more recent Vector 150 and Vertex 460 have fewer reports of problems than we've seen in the past. The percentages of one-star and otherwise negative ratings are also lower than for some of OCZ's older SSDs.

Online user reviews need to be taken with a grain of salt, of course, and OCZ's more recent drives aren't rated as highly as some of their competition. Still, the anecdotal evidence suggests progress is being made on the reliability front. The internal data OCZ shared with us also shows a reduction in failure rates:

Source: OCZ

According to OCZ, the Vertex 150 and Vertex 460 have much lower return and failure rates than previous generations. The firm credits its switch to in-house controller technology for some of the improvement, and it says getting early access to Toshiba NAND has also helped "to further improve performance and reliability." If these numbers are accurate, the failure rates for OCZ's most recent SSDs are lower than for Intel's business-oriented drives. Seems almost too good to be true.

Unfortunately, reliability isn't something we can easily evaluate independently. But we can quantify the Arc 100's performance in a varied collection of tests—and against a wide range of alternatives. Our performance analysis starts on the next page.