Apple’s brand-new MacBook Air might not look much from the outside, but a revolution lurks under the hood: This is the first mainstream computer to eschew SATA in favor of PCIe SSD! Long heralded in workstations and servers, PCIe SSD brings massive potential for storage performance.
Apple Bets on SSD
Apple was first out of the gate in switching to all-SSD storage for their mainstream computer offering with the introduction of the late-2010 MacBook Air. Then they doubled down in 2012, going all-SSD with the Retina MacBook Pro lineup. And now Apple is bringing “all-SSD” goodness to the Mac Pro, too! Sure, other vendors now offer SSD storage, but no one else has made the switch en masse like Apple.
It’s hard to find a product that still uses a mechanical hard disk drive: There’s the “fat” (non-retina) MacBook Pro, the iMac, and the Mac Mini. Apple doesn’t break out their sales by model line, but desktops make up just about 25% of unit volume, and the MacBook Air is a very hot seller. It’s fair to say that more than half of all Macs sold are models no longer offered with a hard disk drive, and that number could be as high as 75%!
Designing around solid state drives (SSDs) is a tremendous differentiator for Apple. They can create thin and light products (the MacBook Air, Retina MacBook Pro, and iPad) without sacrificing battery life or performance. On the contrary, with two orders of magnitude better I/O performance, SSD-based products delight users much the same way Intel’s massive CPU speedups used to, back in the day. Fast storage has become the differentiator in a crowded and mature market.
Moving From SATA to PCIe SSD
When Apple introduced their all-SSD MacBook Air, I speculated that it wouldn’t be long before the company ditched the SATA bus in favor of PCI Express (PCIe). After all, at just 3 Gbps, SATA can’t compete with 10 Gbps from a simple PCIe 2.0 x2 connection! And the company is already betting strongly on (PCIe-based) Thunderbolt for expansion. Thanks to Thunderbolt, current Macs have much faster potential external storage performance than their internal drive can manage!
But “blade SSDs” using SATA were more than sufficient for Apple’s needs in 2011 and 2012. Indeed, many (including me) praised the amazing performance of these devices in our Retina MacBook Pro and MacBook Air laptops. They offered remarkably speedy performance and compact dimensions balanced by low power draw and reasonable affordability.
But time moves on. As early as 2010, Toshiba introduced PCIe SSD blades to the market, but apparently found few takers. PC makers did switch to all-SSD designs, especially when it came to tablets and Ultrabooks, but they too decided on mSATA or other SATA blade designs. Those of us “in the know” kept our eyes peeled, spotting PCIe SSD modules in enterprise products like the Dell PowerEdge G12 servers but nowhere in consumer products.
That all changed this week, as Apple revealed the new Mac Pro and MacBook Air lineup for mid-2013. As suspected, both product lines have gone all-PCIe for their SSDs, presaging a new performance jump for Apple. And sure enough, initial benchmarks are eye-popping, with the MacBook Air delivering nearly 800 MB/s! One expects the Mac Pro to meet the reported 1-1.2 GB/s throughput to its own PCIe SSD.
Although these new PCIe “blade” SSDs appear similar to the previous SATA devices, they are a whole new animal. Apple appears to be using two 5 Gpbs PCIe 2.0 lanes for each SSD (aka, PCIe 2.0 x2), but this could change in the forthcoming Mac Pro. One imagines PCIe x4 connectors with double the performance, and PCIe 3.0 is an option as well. With 20 Gbps Thunderbolt 2, it’s not unreasonable to imagine 20 Gbps PCIe SSDs in Mac Pros!
I’ve heard that Apple is using both Toshiba and Samsung PCIe SSDs in the MacBook Air. And I’ve heard rumors that a SanDisk part could be on the roadmap, too. Exciting times!
Stephen’s Stance
The “Apple doesn’t innovate” crowd won’t like hearing this, but Apple is at the lead when it comes to pushing high-performance storage to the masses. First it was two all-SSD lines, then automated storage tiering, and now PCIe SSD in a mass-market product. This is good for the industry generally, and the storage segment in particular!