Minisforum UM790 Pro Upgrade Guide: RAM, SSD and CPU

Updated Oct. 27, 2026 · Written from this device's verified specifications

The UM790 Pro is one of the friendlier mini PCs to upgrade. Memory and storage are both socketed and reachable behind the case cover, and neither upgrade needs special tools beyond a standard screwdriver. The processor is a different story — it is fixed to the board and can never be swapped. Here is what fits, what the limits are and what to look out for before you buy.

At a glance

  • 2x DDR5 SO-DIMM slots, up to 64 GB total (2x 32 GB), 5600 MT/s supported maximum
  • 2x M.2 2280 NVMe slots, PCIe 4.0 x4, RAID 0/1 supported
  • No 2.5-inch SATA bay, no memory card reader and no free M.2 2230 slot
  • CPU is soldered (Ryzen 9 7940HS) — no CPU upgrade is possible
  • 2x USB4 (40 Gbps) for fast external storage if the inside is full
2x DDR5 SO-DIMM (dual-channel)2 × DDR5 SO-DIMM · up to 64 GB total · 5600 MT/s
2x M.2 2280 NVMe (PCIe 4.0 x4)2 × SSD M.2 2280 (NVMe) · up to 2.048 TB
2 × SO-DIMM · DDR5up to 64 GB total2x M.2 2280 NVMe (PCIe 4.0 x4)2 × SSD M.2 2280 (NVMe) · up to 2.048 TB
Schematic of the upgradeable slots (not to scale). Check the owner's manual for their exact positions.

Lifecycle and support

A current model: sold new and supported.

20232024202520262027Today11 · Release · May 23, 2023
Filled dots: dates published by the manufacturer. Hollow dots: estimates from third-party sources.
MilestoneDate
Release
First available to buy.		 May 23, 2023 Estimate First availability (China): '铭凡宣布 UM790 Pro 迷你主机于今日正式发售', on sale 2023-05-23. This is the first date the product could be bought, per the release definition.
Source ↗

Dates not listed haven't been published by the manufacturer or a reliable third party.

RAM: up to 64 GB across two SO-DIMM slots

The UM790 Pro has two DDR5 SO-DIMM slots running in dual-channel mode. Nothing is soldered to the board, so whatever memory is in there now can be removed and replaced. The maximum supported configuration is 2x 32 GB for 64 GB total, and the supported maximum speed is 5600 MT/s.

What fits: standard DDR5 SO-DIMMs (the laptop-style modules), non-ECC and unbuffered. ECC and registered memory are not supported. Modules are limited to 32 GB each.

What to watch out for: 5600 MT/s is the figure on the spec sheet, but many budget modules actually run at 4800-5600 MT/s depending on their JEDEC profile and what the BIOS allows. If a cheaper kit lands at 4800 MT/s that is normal behaviour, not a fault. The instruction manual shows the modules being inserted at a 45-degree angle with the notch aligned before pressing them flat — worth a look before you start so you do not force anything.

A 40 mm fan cools the memory and SSD area, so don't stack anything over it or block the airflow once the case is back together.

Buying tips

  • Buy a matched kit of two modules rather than one stick, so you get dual-channel performance from the start.
  • 32 GB per module is the ceiling — 2x 32 GB is the biggest configuration this machine supports.
  • Non-ECC, unbuffered DDR5 SO-DIMM only. Desktop DIMMs and DDR4 will not fit.
  • Don't pay a premium for very high clock speeds; the platform tops out at 5600 MT/s and budget kits often run a little below that.

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Storage: two M.2 NVMe slots, and no SATA at all

There are two M.2 2280 (22x80 mm) NVMe slots, both PCIe 4.0 x4. The manufacturer's spec pages state no capacity limit, while the third-party-hosted instruction manual says up to 2 TB per slot. Treat 2 TB as a conservative qualification figure rather than a hard wall — larger drives generally work, but the only figure on paper is 2 TB.

Both slots can be combined in RAID 0 (speed) or RAID 1 (mirroring). Keep in mind that RAID is a firmware/BIOS feature and means rebuilding the array if you change drives later.

What does not fit: there is no 2.5-inch SATA bay in this model (some other Minisforum models have one — this one does not), no memory card reader, and the M.2 2230 A/E-key slot inside is already occupied by the Wi-Fi 6E/Bluetooth module, so it is not a free storage slot.

What to watch out for: a 40 mm fan cools the SSD area. Hot-running Gen4 drives can throttle if airflow is blocked, so keep the fan path clear. If you end up needing more capacity than two internal drives provide, the two USB4 ports (40 Gbps) will run an external NVMe enclosure at close to full speed. Early units had reports of unexpected shutdowns and sleep problems, so update the BIOS and drivers before you rely on the machine for anything critical.

Buying tips

  • Any M.2 2280 NVMe drive fits physically; PCIe 4.0 is what the slots provide, so a Gen4 drive is the sweet spot.
  • If you want cheap bulk storage internally, this is the wrong machine — look at a model with a SATA bay or add USB-attached storage.
  • Don't buy a 2230 drive expecting a free slot; the A/E-key slot is taken by Wi-Fi.
  • Prefer drives with reasonable thermal behaviour and leave the SSD fan unobstructed.

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Frequently asked questions

How much RAM can the Minisforum UM790 Pro take?
64 GB total, in a 2x 32 GB configuration. Each DDR5 SO-DIMM slot accepts up to 32 GB.

Can I use DDR4 in the UM790 Pro?
No. The two memory slots are DDR5 SO-DIMM only. DDR4 modules will not fit physically or electrically.

Does the UM790 Pro support ECC or registered memory?
No. Use standard non-ECC, unbuffered DDR5 SO-DOMMs — nothing on the spec lists points to ECC support.

How many SSDs fit in the UM790 Pro?
Two M.2 2280 NVMe drives, both PCIe 4.0 x4. They can be run individually or as RAID 0/1.

Can I add a 2.5-inch hard drive or SATA SSD?
No. There is no SATA bay in this model. Internal expansion is limited to the two M.2 slots; anything else has to be external, and the two USB4 ports (40 Gbps) are the fastest way to do that.

Can I upgrade the CPU?
No. The Ryzen 9 7940HS is soldered to the motherboard, so there is no socket and no compatible replacement.

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How to upgrade

Before you start

  • Back up your data before changing any drive.
  • Power off and unplug the machine before opening it.
  • Ground yourself to avoid static damage.
  • Follow the owner's manual for opening the case — screw and clip placement is model-specific.
  • Install RAM at a 45-degree angle with the notch aligned, as the instruction manual shows.
  • Check the BIOS/firmware recognises the new RAM total and drives afterwards.
  • Consider updating the BIOS and drivers early — early units had shutdown and sleep reports.

Good to know

  • Minisforum publishes no capacity limit for the M.2 slots, while the third-party-hosted instruction manual states 2 TB per slot — treat that as a conservative qualification figure rather than a hard limit.
  • Some spec listings say Bluetooth 5.2 and others say 5.3. The inconsistency is a paperwork one and does not affect memory or storage upgrades.
  • Minisforum publishes no official TDP figure; the 65 W number in circulation comes from a third-party listing and should be treated as an estimate.
  • The supported memory speed is 5600 MT/s, but actual running speed depends on the module's JEDEC profile and the BIOS — budget modules commonly run at 4800-5600 MT/s.
  • The SSD area is actively cooled by a 40 mm fan; hot Gen4 drives may throttle if airflow is blocked.

Frequently asked questions

How much RAM can the Minisforum UM790 Pro take?

Up to 64 GB total, using two 32 GB DDR5 SO-DIMMs in the two dual-channel slots.

Does the UM790 Pro support ECC or registered memory?

No. The spec lists point to standard non-ECC, unbuffered DDR5 SO-DIMMs (laptop modules).

How many SSDs can I install?

Two M.2 2280 NVMe drives, both PCIe 4.0 x4, with optional RAID 0 or RAID 1 across them. Minisforum publishes no capacity limit; the third-party-hosted manual says 2 TB per slot, which is best read as a conservative qualification figure.

Does it have a 2.5-inch SATA bay?

No. There is no SATA bay and no memory card reader in this model. For extra capacity, use the two USB4 ports (40 Gbps) with external storage.

Can I replace or upgrade the CPU?

No. The Ryzen 9 7940HS is soldered to the board (FP7/FP7r2 BGA), so there is no CPU socket and no upgrade path.

Is the Wi-Fi card slot free for a third SSD?

No. The M.2 2230 A/E-key slot is occupied by the Wi-Fi 6E/Bluetooth module and is not available for storage.

Official documents and references

This guide was written with AI assistance from the compatibility data PartsPrices verified against the manufacturer's documents. Always check your exact model and the owner's manual before buying or opening your computer.