There’s evidence to suggest that original M1 Macs write more slowly to external SSDs in some configurations. Does this extend to later models with M1 Pro or Max chips?
Stibium
Before deciding on internal and external storage, you need to be realistic about the performance it will achieve. Here are the numbers – and a couple of things we tend to forget about.
It’s limited to 5 Gb/s, giving read rates of about 400 MB/s and writes at about 430 MB/s. Fine for Time Machine backups, but bad with NVMe drives.
Select a test, time it, and compare the result with those from other systems. Choose whether to use a synthetic or application benchmark, and don’t forget your confirmation bias.
Which is faster, a MacBook Pro 16-inch with an M1 Pro, or a Mac Studio with an M1 Max? Tests cover P and E cores, Neural Engine, SSD and more.
All disks cache data to be written, which makes benchmarking them tricky. It has more serious consequences which macOS tries to allow for in file systems and backups.
Have you got problems backing up to your NAS? Here is a series of four simple tests to perform to give clear insights and help you tune its performance.
How to measure read speed on storage using 1600 files totalling over 320 GB, enabling comparison between internal and external SSDs.
Progress benchmarking performance of internal SSDs in M1 Macs: tests of 400 files totalling over 130 GB written and read in less than 50 seconds. And results.
Fast compact external SSDs are prone to thermal throttling. This is demonstrated during tests writing 96 files, when transfer rates fell from 2 GB/s to around 700 MB/s.
The Eclectic Light Company 