The M6 Mac mini starts at $899 with 256GB of storage, and Apple asks $200 more for the 512GB model. The extra $200 buys a faster SSD as well as capacity, and none of the storage can be upgraded later.
Benchmark testing with Blackmagic’s Disk Speed Test found that the 256GB configuration reads and writes at roughly half the speed of models with 512GB or more. The M5 Pro Mac mini has the same storage layout, and both models have been on sale since September 22.
The 256GB Model Has Half the Read Speed of the 512GB Model
The gap comes down to how the storage is built. The 256GB configuration uses a single NAND chip, while the 512GB and larger models use two, which lets the drive move data in parallel.
- M6 Mac mini with 256GB: about 3,217 MB/s read and 3,000 MB/s write
- M6 Mac mini with 512GB: about 6,371 MB/s read and about 6,577 MB/s write
- M4 Mac mini with 256GB, for reference: about 2,793 MB/s read and 2,015 MB/s write
The 256GB M6 model is still faster than the M4 it replaces, with write speeds up nearly 49 percent and read speeds up about 16 percent. Most people browsing, streaming and working in office apps are unlikely to feel the difference. Large file transfers, video caches, swap-heavy workloads and loading local AI models can benefit from the faster drive.
Soldered Storage Makes the Choice Permanent
The new models return to soldered storage, so the drive cannot be swapped out later. The M4 and M4 Pro Mac mini models had removable storage, and the maker of the upgrade modules for those models says support for the M6 and M5 Pro now looks unlikely.
External drives are still an option for extra capacity, but they do not replace the internal drive’s speed, and the internal SSD is where macOS and your apps live.
Apple Intelligence Adds Another Reason to Pay for 512GB
Apple lists up to 14GB of on-device storage for Apple Intelligence on Macs with an M3 chip or later, and it has been measured at up to 30GB on some machines. On a 256GB drive, that is roughly 12 percent of the total before you add a single file. If you already run short on room, the guide to freeing up Mac storage covers the safe options.
The 512GB Configuration Makes Sense for Main Computers
- Buy 512GB if the Mac mini is your main computer, you edit video, you work with large files or you plan to run local AI models
- Buy 256GB only if the $200 matters and you already plan to keep most files on external drives or in the cloud
Our Take
I would spend the $200 on the 512GB model. You get double the read speed and more room for Apple Intelligence, and you avoid being locked into a small drive that cannot be upgraded. The 256GB model makes sense as a secondary machine.
