Apple's iMac, MacBook Pro lines are SSD friendly

Apple's new iMac line-up, unveiled earlier this week, includes technology that better marries the popular all-in-one desktops to the speedy NAND flash storage that Apple is using in more and more of its computers.

The updated all-in-ones, which sport Intel's latest Core-series processors, are based on Intel's Z68 chipset for Sandy Bridge. That chipset, which an Apple spokesman confirmed is indeed being used, allows the iMac to use a speedy solid-state drive (SSD) as a boot and application drive in tandem with a traditional hard disk drive, which is used for mass storage of files and data.

Once available only on the highest-end 27-in. model, the built-to-order SSD option is now available for all but the cheapest iMacs, including a 21.5-in. version that starts at $1,499. Instead of getting a single hard disk drive, you can order a 256GB SSD and either a 1TB or 2TB hard disk, for an extra $600 or $750, respectively.

The Z68 chipset supports Intel's Rapid Storage Technology SSD caching, which allows the SSD to speed up OS and application load times and access frequently used data faster. (The iMac on Thursday also got a firmware upgrade, enabling it to use its 6Gbit/sec throughput on the drives. That throughput matches the SATA 3.0 specification used in the latest SSDs, paving the way for the iMac to get the utmost from future SSDs.)

Users who opt for the SSD/HDD combo should notice a difference in performance compared to models with only a standard hard drive.

Apple's move toward flash memory storage began with the MacBook Air in 2008, which offered a 64GB SSD as an option. The second-generation Air, released last fall, uses NAND flash memory exclusively for storage -- it's actually part of the ultra-thin laptop's logic board. On-board flash is different from the SSDs or hybrid disk drives like the Momentus XT that you can install yourself. The latter uses a disk-drive form factor.

Apple isn't alone in opening the doors to flash encroachment on traditional hard drives. All-in-one hybrid models like the Momentus XT that combine NAND flash and spinning disks in the same drive are already on the market. To date, Seagate has been the main supplier of those drives, although Samsung dipped its toe in the market four years ago with the HDD-FlashON line. But it has done nothing with hybrids since. Recently, however, hard disk drive maker Seagate strengthened its ties with worldwide NAND flash producer Samsung -- a deal that industry analysts think will result in faster development of the kind of hybrid drives that could take advantage of the Z68 chipset in the new iMacs.

On top of that, Intel -- which worked closely with Apple on the new Thunderbolt connectivity technology -- is making noises about its own hybrid drives, which could spur drive development to move even faster.

The iMac isn't the only recent Apple product to become more SSD friendly. The MacBook Pro models unveiled in February are also optimized to take better advantage of SSDs.

The latest MacBook Pro models use the SATA 3.0 specification for the internal drive connection, which can take full advantage of a new breed of SSDs that also use the latest 6Gbit/sec SATA specification. (It's the same connection speed yesterday's iMac firmware update enabled.)

In stock form, the new MacBook Pro comes with a 750GB 5400rpm hard disk drive. But Apple allows customers to upgrade the laptop with one of three capacities of SSD: 128GB, 256GB or 512GB. Moving to an SSD significantly boosts the computer's speed but adds hundreds of dollars to the final price, depending on which model you're buying.

The SATA 3.0 specification is important because it doubles the bandwidth over SATA 2.0 from 3Gbps to 6Gbps. Given that SSDs can send bursts of data at speeds beyond 3Gbps, the higher bandwidth means potentially more speed in the future.

IDC Analyst Jeff Janukawicz said SATA 3.0 is important because of an SSD's vastly better performance over a hard disk drive, particularly in server-client architectures.

"When an SSD is coupled with the latest generation SATA 6Gbps interface, it will deliver the most throughput for demanding client systems," he said. "As a result of accelerating storage I/O, users can expect faster access data, quicker application loads, and boost to overall system performance."

But for desktops and laptops, the same is not true.

According to Michael Yang, an SSD analyst with research firm iSuppli, because read/write operations in consumer devices occur mostly in bursts of I/O, they're not likely to take full advantage of the 6Gbps throughput SATA 3.0 offers. In general, he's only seen a 10 per cent to 20 per cent performance increase in SSDs using SATA 3.0 connectivity.

"Sure, [the throughput] is 2X, but fundamentally, the flash hasn't changed, and the performance change will come from the SSD's controller design," he said.

As SSD performance continues to scale, however, with some drives achieving 500MB/sec or more in throughput, greater bandwidth will make more of a difference.

The top-end Apple MacBook Pro now uses the SATA 3.0 specification for the internal drive connection, which offers 6Gbps link speed.

Lucas Mearian covers storage, disaster recovery and business continuity, financial services infrastructure and health care IT for Computerworld. Follow Lucas on Twitter at @lucasmearian or subscribe to Lucas's RSS feed. His e-mail address is lmearian@computerworld.com.

Key words:

Read more about macintosh in Computerworld's Macintosh Topic Center.