M4 Mac mini Teardown: Upgradable Storage, Powerful, and Tiny
Apple's redesigned M4 Mac mini gets torn down: tiny, densely packed, with upgradable storage. Does it hold up to repair scrutiny? Find out.
Apple has redesigned the Mac mini from the ground up. The new model is markedly smaller than its predecessor. It resembles a miniature Mac Studio, with the same aluminum finish, which is prone to fingerprints. A side-by-side comparison with the M1 Mac mini shows a substantial reduction in size. Lumafield provided a preview of the internal layout, which shows how densely the components are packed.
Design Changes
- Power supply: The power supply unit is no longer a single module. It is a board that extends across the top of the case, a layout similar to the HomePod.
- Power button: Apple moved the power button from the back of the device to the bottom plate. The change has drawn both criticism and defense. Third-party 3D-printed solutions are available to address the change.
Teardown Procedure
Removing the Bottom Plate
The aluminum shell is solid, so the device must be turned over to access the bottom plate. The plate is held by clips. A pick can be inserted between the seams without causing damage. Each corner is secured by four clips, which must be unlatched individually.
Disconnecting the Power Button
The power button sits in a corner near the cables. It was the first component disconnected.
CMOS Battery
The CMOS battery is a CR1632 lithium button cell. Like all lithium batteries, it is a consumable that requires periodic replacement. The CR1632 is a widely available standard.
Removing the Inner Plate
- Four outer screws secure the inner plate to the chassis.
- Four further screws secure the thermal assembly to the plate.
On the underside of the plate, a flex cable is secured under a smaller circular plate. Based on the coaxial cables connected to it, the component is likely the wireless module.
Removing the Fan
The fan occupies about half the space on this layer of components. The M4 Mac mini uses an entirely redesigned thermal management system, and the fan performs a central role in keeping the M4 chip cool.
Thermal Management
The base of the Mac mini draws in air from the surrounding environment. Air circulates through the device and exits through the bottom.
The cooling solutions differ between models:
| Model | Heatsink |
|---|---|
| M4 Pro | Larger copper heatsink |
| Base M4 | Smaller aluminum heatsink |
The M4 Pro uses a larger copper heatsink because its more powerful chip requires greater cooling capacity.
Storage
Single NAND Module
The M4 Mac mini uses a single NAND storage card. The Mac Studio has two ports, while the M4 Mac mini has only one.
Upgrade Test
The team compared a 256 GB module with a 512 GB module. The two cards are identical except for the NAND chips. The team swapped the modules between machines. After running the swapped module through Apple Configurator, the system functioned correctly. The test confirmed that storage upgrades are possible.
Module Compatibility
The NAND modules are not identical across all models:
- The base M4 and M4 Pro use physically different modules that are not interchangeable.
- Attempts to boot an M4 Pro with a standard M4 drive produced multiple issues.
Users must confirm they purchase the correct drive for their specific model before upgrading.
Front and Rear Ports
Front Ports
The modular front ports must be removed before the speaker and logic board can be accessed. Removable, replaceable ports improve repairability. These ports experience significant mechanical wear from repeated plugging and unplugging. Replacing them without desoldering is a major advantage.
The front-facing headphone jack is a positive feature.
Rear Ports
- Two screws secure the heatsink on this side of the board.
- A large screw pillar must also be removed. Its Torx screws require the largest bit in the Mako kit.
- After the screws are removed, the rear ports slide up and out. This releases the logic board from the shell.
The rear ports are soldered to the board. This limits repairability.
Logic Board and Memory
Before the logic board can be fully removed, the cable connecting it to the power supply unit must be disconnected.
A plastic layer protects the logic board from the exposed power supply unit. The layer appears to be glued in place. It also adheres to a copper thermal layer that covers most of the underside of the logic board.
Four screws, hidden beneath the copper film, secure the thermal management system to the M4 System on Chip (SoC).
Memory
The M4 RAM is integrated into the SoC architecture. It is soldered and cannot be upgraded. Soldered RAM provides performance benefits.
Repairability Assessment
The teardown identified the following strengths:
- Modular design
- Ease of access to the interior
- Day-one repair manuals
- User-upgradable storage
The teardown identified the following weaknesses:
- Soldered rear ports
- Non-upgradable RAM
The M4 processor, combined with upgradable and removable storage, may allow consumers to use the device for at least a decade. This estimate assumes the logic board does not fail.
Verdict
The Mac mini M4 and Mac mini M4 Pro received a provisional repairability score of 7 out of 10.
Introduction and Design
The redesigned M4 Mac mini is dramatically smaller than the M1 model, with a densely packed interior and a new power supply board that spans the top of the case.
- The M4 Mac mini has an aluminum finish that is a fingerprint magnet.
- A side-by-side comparison with the M1 Mac mini shows a much smaller footprint.
- Lumafield provided a sneak preview of the internal layout via scanning.
- The power supply is no longer a single module; it is a board extending across the top of the case, similar to the HomePod.
- The power button moved from the back to the bottom plate, a controversial change that 3D printed solutions can address.
Opening the Case and Removing the CMOS Battery
The bottom plate is removed by prying clips at each corner. The power button is disconnected first, and the CMOS battery is replaced.
- The bottom plate is held by clips; a pick can separate the seams without damage.
- Four clips secure each corner of the bottom plate.
- The power button is the first component disconnected.
- The lithium CR1632 button cell battery is a consumable and is widely available.
- A Sony PS5 Pro teardown was also underway at the time.
Removing the Inner Plate and Fan
The inner plate is removed by unscrewing eight screws, and the fan is removed. The fan, which takes up about half the space in this layer, is part of a redesigned thermal system.
- Four outer screws secure the inner plate to the chassis.
- Four further screws secure the thermal assembly to the plate.
- A flex cable under a small circular plate is likely the wireless module.
- The fan takes up about half the space on this layer of components.
- The base pulls in air from the environment, which circulates through the device and vents out the bottom.
Thermal Design and Storage Upgrades
The M4 base model uses an aluminum heatsink while the M4 Pro uses a larger copper heatsink. Storage is a single NAND card, and the reviewers swapped 256GB and 512GB modules successfully, though base M4 and M4 Pro modules are not interchangeable.
- The M4 Pro has a larger copper heatsink, while the base M4 has a smaller aluminum heatsink.
- The Mac mini has a single NAND storage port, unlike the Mac Studio's two.
- A 256GB and a 512GB module are identical except for the NAND chips.
- Swapping modules and running them through Apple Configurator worked, so storage upgrades are possible.
- The base M4 and M4 Pro use physically different modules and are not interchangeable; booting an M4 Pro with a standard M4 drive caused issues.
Removing the Speaker and Logic Board
The speaker is removed, and the modular front ports must be removed before the logic board can come out. The rear ports slide out to release the board.
- The speaker is easy to remove.
- Modular front ports must come out first, and they are replaceable without desoldering.
- The front headphone jack is a highlight for audio enthusiasts.
- Two torx screws on the heatsink and a large screw pillar are removed, with a large torx bit from the Mako kit.
- The rear ports slide up and out to release the logic board from the shell.
- The logic board is disconnected from the PSU cable, and a plastic layer and copper thermal film are beneath it.
Logic Board, RAM, and Repairability
Four screws beneath a copper thermal film secure the thermal management system to the M4 System on Chip. The RAM is soldered and not upgradeable, but storage is user-replaceable.
- Four screws hidden under the copper film secure the thermal management system to the M4 SoC.
- The RAM is tightly integrated into the SoC and is not upgradeable.
- Soldered RAM offers performance gains.
- Day-one repair manuals and modular design are praised.
- Soldered rear ports are a downside for repairability.