Sourcing High-Speed Storage for Mac Pro 4K Editors
If you're making the jump to 4K editing and find yourself needing a jolt of capacity and speed, don't expect external SSD drives to come close to the performance of internal drives on your Mac Pro (or most computers). Read on for some alternative solutions.
So you bought a new Mac Pro for video editing, lured by its unique combination of raw power and small form factor. 思考未来, you bought the maximum 1 TB of storage, thinking it would be sufficient for most projects, which you could save off to slower, external storage for archiving. 现在是更长的, 4K项目已经通过了, and you need fast extra storage for project files and the like.
如果你像我一样, one of the first things you did after setting up the Mac Pro was to test the speed of its internal SSD drive, 这是非常惊人的. I did when I received the Mac Pro I rented from 视效技术 for a recent consulting project. I downloaded the Blackmagic Design Disk Speed Test, and saw the awe inspiring results shown in 图1(下面).
图1. The inspiring Write/Read performance of the internal SSD drive on the Mac Pro.
My project absolutely needed an external drive. Knowing that the Thunderbolt connection is much faster than even the speed shown in 图1, I thought that a Thunderbolt-based SSD drive would duplicate the results of the Mac’s internal drive. 所以我买了 1GB Transcend StoreJet 500 Portable SSD drive 在亚马逊售价565美元.
Do the math, and you get a cost per GB of $565, highlighting that cost is the major downside of SSD. Like anything else, however, sometimes you have to pay for speed, and I was willing. Then I pointed Disk Speed Test at the drive, only to see the discouraging results shown in 图2(下面).
图2. The depressing performance statistics on the Transcend external Thunderbolt drive.
这一切都是关于联系
是什么让? SSD就是SSD，对吧? 好吧，是也不是. An SSD drive is an SSD drive, but the connection to the drive controls performance. 在Mac Pro上, the connection to the internal drive is via PCI Express (PCI) bus, which basically is the same connection as the slots in a desktop computer that you plug graphics and other peripheral cards into. Interestingly, it’s also the same technology used in Thunderbolt, which is why Thunderbolt is so fast.
What about the connection to the external drive? 好吧, that’s obviously via Thunderbolt, but the technology controlling the external drive is 萨塔, the same technology that controls most traditional drives. And that’s the bottleneck, or at least the major component of it.
想要证明? 图3(下面) shows the Mac’s Disk Utility report from the two drives. On top is the Macintosh HD, connected via PCI. On the bottom is the Transcend drive, connected via the much slower 萨塔 connection.
图3. 谜团解开了. The internal drive connects via PCI, the external via 萨塔.
The Cliff Notes version is that PCI is much faster than 萨塔, so the Mac’s internal drive is much faster than external drives controlled via 萨塔. If you’d like to learn more about the differences, there’s a great article on Overclock entitled SSD接口对比: PCI Express vs. 萨塔.