Tim: Our tests on a Mac Studio show 2.6 GB/sec read and 2.7 GB/sec write on RAID 0. I’ll report back on what they say in a future article. Both BMD and AJA are investigating apparent testing errors in their programs. Larry continues: As well, I found BMD Disk Speed Test to deliver much more consistent results. What is it with AJA System Test?įollow-up comment from Larry: In additional testing after sending my questions to OWC, AJA System Test (full version) reported RAID 4 speeds at 1/3 the expected throughput for writes and 1/2 expected throughput for Reads. Larry: When measured by BMD, write speeds for a 4-drive RAID 4 is ONE-THIRD the speed of a 4-drive RAID 0. OWC Envoy Pro is a single NVMe SSD blade that connects via Thunderbolt 3/4 and is bus powered. It connects via Thunderbolt 3/4 and has an external power supply. It can be formatted in a variety of configurations: JBOD, RAID 0, 1, 4, 5, and 1+0. OWC Thunderblade is a 4-blade (a “blade” is the SSD equivalent of a hard drive) NVMe SSD RAID. All other Macs require a Thunderbolt solution, which is much slower. We see 17 GB/sec read and write on a 16-blade RAID 0 volume.įollow-up comment from Larry: The Accelsior is a plug-in PCIe card that only supports the 2019 Mac Pro for Mac systems. Our current maximum speed measured on macOS is with 2 Accelsior 8M2s in a 2019 Mac Pro. AJA revs usually produces a new version in a couple of days and BlackMagic seems to take a month or more. In addition, many times when we create a faster storage array we bump up against the maximum speed the tools can handle.

It also lacks the graphing which I have found invaluable for determining if there is an architectural problem in the hardware or software of an OWC storage solution. I find that it is much harder to get reproducible values from BlackMagic Disk Speed Tool than from AJA System Test. I think it is really great if you want to see whether your particular format will work on a given volume, but for reliable testing, it is too limited. Tim: I have always avoided using Blackmagic Disk Speed Tool. Larry: The speeds measured by AJA System Test Lite and Blackmagic Disc Speed Tool vary by HUNDREDS of MB/second. I just did a quick test and, using AJA System Test (full), RAID 4 was about 16% faster than RAID 5 for both read and write.

However, BMD only supports up to 5 GB and AJA only supports up to 16 GB test files for ProRes media, which is the most appropriate format for most video editors. At that time, I’ll run it using using the largest files that BMD and AJA support. Larry replies: Tim, I plan to redo all my tests when I publish an update to my speed testing article. By using a 64 GB test file in AJA System Test, I can ensure that I are not just writing to the file system cache or the faster cache chips on the NVMe blades. So with a RAID 0 volume using 4 of these blades, the first 8 – 16 GB might be going into the cache on the blade. The size of these caches is usually 2 – 4 GB. In addition, many NVMe blades use DRAM caches or SLC flash as a type of cache (SLC flash is much faster than TLC). If I then run AJA System Test with a 64 GB test file, I know for certain that the file cannot reside entirely in the macOS file system cache, there just isn’t enough physical RAM. If I use a Mac with this size RAM, I know that there is no more than 4 – 6 GB available for file system cache. Tim Responds: Unlike most video professionals, I tend to use Macs with smaller amounts of RAM (e.g. I sent them to OWC, BMD and AJA for evaluation and all three companies are looking into this further. When I read Tim’s comment, I went back and re-ran all my tests using AJA System Test (full version). He is using the full version of AJA System Test and not the Lite version available on Apple’s Mac App Store.įollow-up comment from Larry: The AJA System Test (full version) is available from the AJA website.

Here is our conversation.Īt the start of his interview, Tim noted that when he discusses speed numbers in this conversation, he’s using AJA System Test with a 64 GB test file, file system cache disabled and 16 bit RGBA codec. To learn more, I emailed a series of questions to Tim Standing, VP of Software Development at OWC. It is currently not possible to know with any assurance that the test results we see are accurate. NOTE: For example, this article describes the challenges in measuring storage performance using Blackmagic Design vs. What I discovered is that storage “performance,” that is the speed our storage transfers data, is surprisingly variable and complex. I looked at single hard drives, servers and, now SSDs and RAIDs. For the last several weeks, I’ve explored just how fast our storage actually is.

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