Every graphic-heavy application I have used has recommended storing files it uses on a separate disk from the boot disk (preferably an SSD), however with the new MP this isn't an option. The only way to utilise a second drive is as an external drive.

I'm assuming this isn't a problem in terms of performance, and from what I've read MPs are very performant, but why is this? Why can a Mac Pro get away with a single drive when most apps recommend using separate drives for boot and resources?

  • 1
    it doesn't really 'get away' with a single drive. I think you're fully expected to plug a massive Thunderbolt RAID in the back of it.
    – Tetsujin
    Feb 1, 2015 at 13:16
  • @Tetsujin But the speed of a RAID will be less than an internal SSD. Feb 1, 2015 at 14:18

2 Answers 2


Thunderbolt 2 supports data rates of up to 20 Gb/sec. The newest SATA spec, V3.2, only does 16 Gb/sec. There should thus be no difference in performance between an internal SSD (connected via SATA) and an external SSD (connected via Thunderbolt).


The "store files on a separate disk" advice is for many reasons, one of which is getting an extra read/write head into the process. As SSDs have no latency, and bus speeds are many times faster* than they used to be, the main reasons are mostly no longer valid.

It's still a good idea for other reasons, but on a Mac Pro an external Thunderbolt drive won't slow you down any especially if it's spinning storage.

  • 133MB/s for PATA vs multiple GB/s for PCIe

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