Mini PC Upgrade Check: RAM, SSD Slots and What Is Soldered

Before you buy a mini PC, find out whether its memory is in removable modules or soldered to the board, and which M.2 slot sizes it has for storage. Removable memory and open storage slots mean you can upgrade later. Soldered memory means the amount you buy is the amount you keep. The maker's spec page and manual settle it.

Small desktops are sold on size, and a few of them achieve that size by soldering parts to the board. That can be fine if you buy the right amount of memory the first time. It is a costly surprise if you plan to add more later and find nothing to add it to. A few checks before you order tell you which kind of mini PC you are looking at.

Memory: removable or soldered?

There are two common designs. In the first, the memory sits in SO-DIMM sockets, the small modules used in laptops. Wikipedia’s article on SO-DIMM says these modules are often used in computers with limited space, including laptops and small-footprint personal computers. Modules can be swapped, so you can upgrade later by buying compatible ones.

In the second, the memory is soldered to the board. Wikipedia’s LPDDR article says that LPDDR memory is usually soldered directly onto the device’s motherboard, to conserve space and improve efficiency, in contrast to DDR memory that is typically installed in removable modules. If a mini PC uses LPDDR, there is no slot to fill later. Whether a particular model does is a fact about that model, so read its spec page.

What to look for on the spec page:

• The memory type. A spec that lists SO-DIMM slots, with a count, means removable memory. A spec that lists LPDDR or onboard memory with a fixed size means soldered.
• The slot count. Two slots allow a pair of modules, one slot allows a single module, and each case has different upgrade options.
• The maximum supported capacity. The maker states this, and it can be lower than what the memory modules in the market allow.
• The memory generation. Wikipedia notes that SO-DIMM generations are not interchangeable in either direction, because modules use different pin counts or notch positions so the wrong type cannot be inserted. Buy the generation your model lists.

Storage: slots, sizes and interfaces

Storage in a mini PC is usually an M.2 SSD, a small stick that screws to the board. Wikipedia’s M.2 article explains how to read the names. A size such as 2280 means 22 millimeters wide and 80 millimeters long, and 2242 means 22 millimeters wide and 42 millimeters long. Sockets that take longer modules generally also take shorter ones, using different screw positions, but a socket built for a short module will not take a long one.

The key matters as well. M.2 modules have notches, called keys, that indicate which interfaces they support. SATA SSDs typically use the B key and NVMe SSDs typically use the M key, and some SSDs use a combined key. The notches are meant to prevent incompatible installations, and host sockets can have one or both key positions populated, which decides which modules they accept. A socket may support SATA drives, PCIe/NVMe drives or both, so read the spec page for what that exact slot supports and do not assume.

Check these on the spec page:

• The number of M.2 slots. A second slot is a real advantage, since you can add a drive without replacing the first.
• The slot size. Match your SSD’s length code to what the slot takes.
• The interface. NVMe or SATA, for each slot. Our M.2 installation guide explains the install itself.
• Other bays. Some models also have a space for a 2.5-inch drive, and the spec page lists it if so.

What the listing may hide

Retail listings are written to sell, not to inform upgrade plans. A listing that says 16GB of memory does not say whether it is removable. A listing that says 512GB of storage does not say whether the slot is free for a second drive. Compare the listing with the maker’s own page, and if they disagree, trust the maker. If the page does not answer the question, ask the seller or the maker before you order, and keep the answer.

Also watch for models sold in several configurations under one name, which is the same problem we cover for laptops in our guide to listings with the same name and different specs. A barebone version may arrive with no memory or storage at all, and a ready-to-run version may have a fixed amount. Read the box contents line closely.

Where to find the real answer

Start with the model number, which is printed on the unit and on the box, not just the product name in the listing. Then look for the maker’s support page for that exact model, where the manual is usually available as a download before you buy. The manual normally contains a section on opening the case and installing memory or storage, and if it has none, that tells you something too. Reviews with photos of the open board can confirm what the manual says, and they show whether the slots are easy to reach.

Opening the case and the warranty

Upgrading means opening the case, and designs differ. Some mini PCs open with a few screws and a lid, others require removing a bottom plate or pulling a tray. The manual or the maker’s support page shows the steps. Before you open one, check the warranty terms for any note about upgrades, and keep the original parts in case you need to send the unit back as it was. Our guide to upgrading laptop RAM and SSD follows a similar process step by step, including static precautions.

Decide how much to buy up front

If the memory is soldered, treat the initial amount as permanent and choose with care. Our guide to which upgrade to do first helps you judge whether memory or storage is the bigger bottleneck for your work. If the memory is removable, buying the smaller configuration and upgrading later is an option, as long as you check that the modules you plan to buy are compatible with the model.

For a wider look at what is on offer, our roundup of mini PCs for home and office and the mini PC category page are a good starting point, and our refurbished business desktops guide covers another route to a small machine. Check each model’s spec page rather than relying on the category.