Apple’s new Mac mini models with M6 and M5 Pro processors have two storage limitations: their NAND memory is soldered to the logic board, and 256GB configurations offer substantially slower SSD speeds than models with at least 512GB of storage.

The findings mean buyers cannot upgrade the internal storage later through an aftermarket module. They also suggest that customers who want the fastest storage performance should avoid the entry-level 256GB configuration.

Storage upgrades are no longer possible

According to Expand Mac mini, the NAND storage in the new Mac mini models is permanently attached to the logic board. That reverses one of the more unusual benefits introduced with the M4 and M4 Pro Mac mini, whose storage modules could be removed and replaced.

Expand Mac mini sells plug-and-play SSD modules designed to function like Apple’s proprietary storage modules. Owners of M4-generation machines could therefore buy a Mac mini with the lowest storage option and install a larger module later, potentially saving hundreds of dollars compared with configuring the computer with more storage at purchase.

That path does not appear to be available for the M6 and M5 Pro models. “We will keep looking for an opening, but support for the M6 and M5 Pro now looks unlikely,” Expand Mac mini said in a blog post.

Apple has not commented on the change. The M4 and M4 Pro models now appear to be an exception rather than a new direction for the Mac mini: systems using the M1, M2, and M2 Pro chips also had storage soldered to the logic board.

256GB Mac mini has slower SSD performance

The new 256GB configurations reportedly use one NAND chip instead of two 128GB chips. That design reduces storage performance compared with models equipped with 512GB or more, according to testing by AAPL Ch. using Blackmagic’s Disk Speed Test.

  • M6 Mac mini, 512GB: 6,371.5 MB/s read and 6,577.4 MB/s write
  • M6 Mac mini, 256GB: 3,216.8 MB/s read and 3,000.2 MB/s write
  • M4 Mac mini, 256GB: 2,792.5 MB/s read and 2,014.5 MB/s write

The 256GB M6 model produced roughly half the read and write scores of the 512GB version in the reported benchmark. Most users are unlikely to notice the difference during everyday tasks, but the gap may matter to professionals moving large files, working with video, or regularly handling other storage-heavy workloads.

What buyers should consider

The 256GB M6 Mac mini still appears to provide meaningfully faster SSD performance than the previous 256GB M4 model. However, buyers who want the highest internal storage speeds should choose at least 512GB from the outset, since replacing the storage later is not expected to be an option.

The single-chip arrangement is not entirely new. The 256GB versions of the M2 and M2 Pro Mac mini also used a single NAND chip, while the M4 and M4 Pro configurations temporarily offered both removable storage and a different 256GB arrangement.