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2022 Mac Studio M1 Ultra: SSD Speed
Related: 2019 iMac 5K, 2019 Mac Pro, 2020 iMac 5K, 4K and 5K display, Apple Mac Studio, Apple Silicon, iMac, iMac 5K, laptop, Mac Pro, MacBook, MacBook Pro, Macs, SSD, video
Unsure which Mac to get or how to configure it? Consult with Lloyd, and see recommended Macs for photographers and videographers.
MPG tested the $7999 Apple Mac Studio M1 Ultra 20-core CPU / 64-core GPU/ 128GB / 8TB SSD , provided on loan for review by B&H Photo, an authorized Apple Mac dealer. Please buy your gear at B&H Photo and OWC/MacSales.com using any link from this site.
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Real world speeds through the file system using diglloydTools DiskTester.
disktester run-sequential-suite --test-size 8G
This test charts the real-world speed for various transfer sizes for both reads and writes, because small I/O sizes are much slower than larger ones.
For example, 32K transfers are (without special caching) extremely inefficient vs 1MB transfers—making 32 I/O calls is inherently slower than one I/O call, e.g., 32 X 32K transfers vs a single 1MB transfer.
Fast small transfers translate to a more responsive system overall, while fast large transfers translate to better throughput for applications processing very large files, or very large numbers of moderate and large files.
If below are out of date: view current Mac wishlist and all current OWC wishlists.
Transfer speed vs transfer size
disktester run-sequential-suite --test-size 8G
The 2022 Mac Studio M1 Ultra shows stunningly fast write speeds. But no SSD can write 32K blocks that fast—clearly there is some caching going on, presumably something that gathers writes together into 512K blocks, which is what the SSD needs. Or maybe the SSD itself has a small amount of very fast RAM onboard. Hopefully that does not mean data corruption if the power cuts suddenly.
Read speed is pretty poor for 32K and 64K and even 128K writes, inferior to many recent Intel-based Macs. Apple is doing something new and wonderful for writes, but reads are well below average until 8MB or larger transfers are done.
See the next test for more weird stuff.

Sustained Performance Filling 6TB of capacity
Test volume size, APFS: 6TB ~= 5.65 TiB.
Write behavior is unlike anything MPG has ever seen in an Apple internal SSD. excepting the 2021 MacBook Pro M1 Max—both computes share the same erratic SSD performance. The behavior is repeatable; this is no anomaly.
To see an abrupt breakdown in SSD write speed for sustained writes suggests a 2-tier flash drive. The plummet occurs at file ~420 of 1000, equating to about 33% of the 8TB flash drive. Which is (within 2%) exactly how the 2021 MacBook Pro M1 Max SSD behaves.
Thermal throttling is highly unlikely. This looks like 2-tier flash behavior.
However, even the degraded write speed under this very heavy (excessive?) load is in line with prior internal Mac SSDs (3.2 to 3.3 GB/sec) on iMac 5K, Mac Pro, etc. When not degraded, the 7GB/sec figure is pretty awesome.
SSD speed “regenerates” after the first test, so long as there is some time in-between. So something two-tier or similar is happening vis a vis the SSD>
The results for reads here are in excellent agreement with the test above: a bit over 5GB/sec, which is far above the ~3.3GB/sec achievable in prior Macs. But a far cry from the cached write speed.
As reader Don H put it for the 2021 MacBook Pro M1 Max, which behaves similarly:
Of course almost no one would have a task that requires this magnitude of data transfer in the real world, and even then the performance is still quite good, even with a slowdown. Short of the PCI-based storage in your Mac Pro this appears to be the fastest storage in any Mac to date. (It’s odd that the early write performance exceeds the read performance by so much, however.)

