Test Setup

The rest of the tests in this review were conducted on our regular desktop testbed, with the OWC Aura Pro X2 installed in an M.2 adapter. As with our usual SSD reviews, these tests run on Windows (ATSB tests) and Linux (synthetic benchmarks) rather than macOS. The older Apple SM0512F SSD is included because it presents a standard AHCI interface that is software-compatible with SATA controllers, but the more recent Apple SM0128G SSD uses a non-standard protocol and cannot be properly detected on non-Apple systems even with the adapter that works for the SM0512F and OWC Aura Pro X2.

Since the rest of these test results are directly comparable to our usual review results, we've thrown in older numbers for a few more SSDs, including two entry-level NVMe SSDs: the Phison E8-based Kingston A1000, and the Intel 660p QLC-based SSD.

AnandTech 2018 Consumer SSD Testbed
CPU Intel Xeon E3 1240 v5
Motherboard ASRock Fatal1ty E3V5 Performance Gaming/OC
Chipset Intel C232
Memory 4x 8GB G.SKILL Ripjaws DDR4-2400 CL15
Graphics AMD Radeon HD 5450, 1920x1200@60Hz
Software Windows 10 x64, version 1709
Linux kernel version 4.14, fio version 3.6
Spectre/Meltdown microcode and OS patches current as of May 2018

Whole-Drive Fill

This test starts with a freshly-erased drive and fills it with 128kB sequential writes at queue depth 32, recording the write speed for each 1GB segment. This test is not representative of any ordinary client/consumer usage pattern, but it does allow us to observe transitions in the drive's behavior as it fills up. This can allow us to estimate the size of any SLC write cache, and get a sense for how much performance remains on the rare occasions where real-world usage keeps writing data after filling the cache.

The 960GB OWC Aura Pro X2's SLC cache is plenty fast, and lasts for about 147GB of writes before performance starts to drop. Initially, it goes down to about 850 MB/s, but just before the 600GB mark it drops again to be only slightly faster than SATA. Performance recovers a bit through this last phase, and ends up almost back up to the respectable second phase speeds. Overall, this behavior is similar to the HP EX950 that uses the same controller, but the EX950 tends to be a bit faster overall.

Sustained 128kB Sequential Write (Power Efficiency)
Average Throughput for last 16 GB Overall Average Throughput

The overall average write speed puts the Aura Pro X2 as only slightly faster than the Apple 500GB drive, and half the speed of the fastest modern TLC drive. But this obscures the fact that the Apple drive doesn't have an SLC cache and never gets much above 800 MB/s during the fill, while the Aura Pro X2 writes at nearly 2.5GB/s for any ordinary real-world duration.

macOS Sequential IO Performance AnandTech Storage Bench - The Destroyer
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  • zepi - Wednesday, June 5, 2019 - link

    Maybe you could list the Mac models that this works with in a nice table? It is not that long of a list.
  • crimsonson - Wednesday, June 5, 2019 - link

    Or you can go to the manufacturer's/seller's website and get the info?
  • hasseb64 - Wednesday, June 5, 2019 - link

    so why did you not post it here then?
  • Ryan Smith - Thursday, June 6, 2019 - link

    Hey, that's a good idea. Thanks! I've gone ahead and added a list.
  • zepi - Thursday, June 6, 2019 - link


    I didn't even realise that this would actually be an upgrade path to my old rMBP13.

    I wonder if the horrible mixed workload performance translate into a meaningfully slow zipping / unzipping performance.
  • leexgx - Monday, June 17, 2019 - link

    maybe should add that its best not to even use these OWC ssds for these macs, as they have not fixed the power state bugs due to the mac it self (more so 2013-2015) and the SSD missing something proprietary (system has a high chance when it comes out of hibernate and crash as the drive is missing on wake up)
  • ltcommanderdata - Wednesday, June 5, 2019 - link


    Being a NVMe drive specifically designed to upgrade Macs, I don't suppose the OWC Aura Pro X2 solves the problem of NVMe drives failing to be detected upon wake from hibernation in 2013-2014 Macs? The current workarounds for that generation of Macs are to either disable hibernation reducing battery life or patching the BootRom which isn't user friendly.

    It would have been interesting to see where Apple's Polaris NVMe drives stack up in your comparison since testing by @gilles_polysoft at Macrumors suggests it's still one of the fastest, most power efficient options compared to third-party SSDs. It was only offered officially in 2017 iMacs though so finding a pull or an Apple service provider willing to sell a new one to upgrade older Macs is difficult and expensive.
  • Skeptical123 - Wednesday, June 5, 2019 - link

    That's a good point
  • zsero - Wednesday, June 5, 2019 - link

    Yes, there is a big difference between 2013-2014 and 2015 Macbook Pros regarding how they work with NVMe drivers. After reading a _lot_ about it, I finally decided that for my 2013 rMBP 15 the best option is to buy an original "SSUBX" drive from eBay, as none of the NVMe drivers would work reliably.
  • MamiyaOtaru - Thursday, June 6, 2019 - link

    "I don't suppose the OWC Aura Pro X2 solves the problem of NVMe drives failing to be detected upon wake from hibernation in 2013-2014 Macs?"

    It does not. https://forums.macrumors.com/threads/owc-launches-... The OWC rep finally acknowledges it after mistakenly saying hibernation was fine for a couple pages. Disappointing lack of knowledge for the products he is shilling

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