What Minisforum's UM780L Slim puts in a 0.77-liter case
Technetbook reported the launch on September 24, and Notebookcheck reported it separately. Both describe the same basic package: a compact mini PC powered by AMD's Zen 4-based Ryzen 7 7840HS CPU, with LPDDR5X-7500 memory, two PCIe Gen4 SSD slots and USB 4 ports in a 0.77-litre chassis. Minisforum's U.S. product listing gives the case as 130 × 126 × 47.2 mm and the weight as 0.6 kg. It also lists wall mounting as supported. The store page suggests you install UM780L Slim behind a compatible display or beneath the desk.
The processor has 8 cores and 16 threads, with a 3.8GHz base clock and turbo up to 5.1GHz, according to Minisforum's specifications. The Phoenix-based Zen 4 processor comes with a Radeon 780M iGPU. Minisforum's U.S. listing says the machine comes with Windows 11 preinstalled.
Technetbook describes the machine as delivering "desktop class speed." That phrase is Minisforum's marketing. Neither report includes independent benchmarks, and the gaming figures on Minisforum's own store page come from the company's internal testing. Until reviewers test the machine, treat any performance claim as a vendor claim.
Soldered LPDDR5X-7500 is the UM780L Slim's defining trade-off
The biggest decision point is memory. You can pair the chip with either 16 GB or 32 GB of LPDDR5X-7500 memory, effectively ruling out DIY memory upgrades. Minisforum's detailed specs list both capacities. However, every configuration currently shown in the U.S. store and every China configuration Technetbook reported comes with 16GB.
Minisforum defends the choice on bandwidth. The company claims LPDDR5X-7500 provides 34% more rated bandwidth than DDR5-5600, which is the only upside of going with soldered RAM, as Notebookcheck puts it. That claim has some basis, since the Radeon 780M has no memory of its own and shares system RAM. How much the extra bandwidth helps in practice has not been independently measured.
Older Slim models show what changed. A retail listing for the earlier UM680 Slim barebone describes 2x DDR5 SODIMM Slot, 4800 MHz (96GB max). The case is close to the same size, and that listing gives it as 130 × 126.5 × 50.4mm(LWH). The UM780L Slim therefore swaps upgradeable SODIMM slots for faster, fixed memory. If your workload could outgrow 16GB, for example virtual machines, big datasets or heavy browser and IDE sessions, this is the spec to think about before checking out.
Two PCIe 4.0 M.2 slots keep UM780L Slim storage open-ended
Storage stays flexible. Notebookcheck says storage remains upgradeable. You get two M.2 2280 slots, both rated at PCIe Gen4, with support for up to 8 TB of storage total. Minisforum's own specs describe both slots as M.2 2280 Key M running at PCIe 4.0 x4. The 8TB total is the company's stated figure, not a tested limit.
The second slot gives buyers some practical options. You can keep the operating system on one drive and put data on the other, add capacity without cloning the boot drive, or buy the cheapest configuration and fit your own SSDs. In China, the base model comes with 16GB of RAM and no onboard storage for 3,159 yuan. Minisforum's U.S. listing doesn't currently offer an equivalent no-SSD configuration.
UM780L Slim ports: USB4, three displays, and one HDMI caveat
The port layout is split between front and back. According to Minisforum's specifications, the front has two USB 3.2 Gen 2 (10Gbps) Type-A ports and a 3.5mm combo audio jack. The back has:
- One USB4 Type-C port running at 40Gbps with DisplayPort Alt Mode and power input/output support.
- Two USB 2.0 Type-A ports, which suit a keyboard, mouse or dongle.
- One 2.5GbE Ethernet jack, which Minisforum says uses a Realtek RTL8125BG controller.
- One DisplayPort 1.4 output and one HDMI 2.1 output.
- The DC power input.
Minisforum lists the USB4 port as accepting 65–100W of power input and supplying 15W of output. It's a useful detail for anyone planning a USB-C monitor or dock setup, though Minisforum hasn't said which docks or monitors it has tested with the port.
For displays, Minisforum states that the system can drive three displays simultaneously, with DisplayPort and USB4 supporting up to 4K at 120 Hz. Notebookcheck adds that the USB 4 port can output an 8K/60 Hz signal. The limits aren't the same on every output. Minisforum describes the HDMI 2.1 port as TMDS and caps it at 4K/60Hz. TMDS is the older HDMI signalling method, as opposed to the FRL method that higher HDMI 2.1 bandwidths use. For comparison, the UM680 Slim listing advertised 1x HDMI 2.1 FRL (Up to 8K@60Hz/4K@120Hz in non-DSC Mode). If you want 4K at 120Hz, use DisplayPort or USB4, not HDMI.
For wireless, the Minisforum UM780L Slim also offers Wi-Fi 6E, Bluetooth 5.2 and a single 2.5 Gbps Ethernet port. Minisforum's spec sheet names the Wi-Fi module as an MT7902.
Power profiles push the Ryzen 7 7840HS past laptop limits
The Ryzen 7 7840HS was designed for laptops, and a mini PC can give it more power. Minisforum gives the Ryzen 7 7840HS considerably more thermal headroom than what is usually allowed in laptops. Performance mode can push the processor as high as 70 W initially and sustain 65 W, while Balanced and Silent modes reduce sustained power to 54 W and 45 W, respectively. Minisforum's full table lists the modes like this:
| Mode | Fast | Slow | SUS |
|---|---|---|---|
| Performance | 70W | 65W | 65W |
| Balanced | 65W | 60W | 54W |
| Silent | 60W | 54W | 45W |
Minisforum doesn't define "Fast," "Slow" or "SUS" on its spec page. Notebookcheck reads them as a short initial boost limit and a sustained limit, which fits the usual meaning of those terms on AMD mobile chips, but the table itself doesn't say so. A blower fan and phase-change thermal material handle cooling. Phase-change material is a thermal interface that softens at operating temperature to fill the gaps between the chip and the cooler.
UM780L Slim noise and NPU claims don't match Minisforum's own tables
Two of Minisforum's marketing claims don't line up with its own spec tables. The first is noise. Technetbook reports that, according to Minisforum, the unit runs at 26dB during idle periods and tops out at 40dB under full load in quiet mode. Minisforum's technical specification lists noise below 40dB only for Balanced mode and marks Performance and Silent as "N/A." Elsewhere on the U.S. store page, the marketing copy says full-load noise stays below 45dB. In other words, Minisforum's published spec gives no full-load figure for Silent mode, and no independent acoustic tests exist yet. Treat 26dB at idle and 40–45dB under load as the manufacturer's range.
The second is AI hardware. According to Notebookcheck, the company also advertises up to 10 TOPS of AI performance, although its detailed specification table curiously lists the NPU field as "N/A". For Windows buyers, 10 TOPS is well below the level Microsoft requires for Copilot+ PC features. Don't buy this machine expecting those on-device AI features.
UM780L Slim pricing and availability by region
Availability depends on the region, and the configurations differ slightly too:
| Market | Configuration | Price | Status |
|---|---|---|---|
| China | 16GB RAM, no SSD | 3,159 yuan | On sale, per Technetbook |
| China | 16GB RAM, 512GB SSD | 3,799 yuan | On sale, per Technetbook |
| China | 16GB RAM, 1TB SSD | 4,299 yuan | On sale, per Technetbook |
| International/U.S. | 16GB RAM, 500GB SSD | $535 | Orderable; ships late October (est.) |
| International/U.S. | 16GB RAM, 1TB SSD | $599 | Orderable; ships late October (est.) |
Technetbook says the UM780L Slim is already available in China, with the global launch expected later in October. International pricing starts at $535 for the 16GB RAM and 500GB SSD model, while the 1TB version costs $599. Both configurations are expected to begin shipping globally in late October. Minisforum's U.S. store shows the same prices and the same "Late October" shipping estimate. That's company confirmation of the price and the planned timing. Being able to order now doesn't mean units are shipping.
China's entry-level model has no SSD, while the cheapest international model comes with a 500GB drive, listed as 512GB in the China lineup. So you can't compare yuan and dollar prices like-for-like. Notebookcheck's headline calls the machine budget-friendly, and at $535 with Windows 11 and an SSD included, the international price is broadly in line with that. The chip, though, is a Zen 4 "Phoenix" part and not one of AMD's current generation.
What this means for you
If you want a small Windows 11 box for office work, a multi-monitor setup or a home-lab client, and 16GB will always be enough, the UM780L Slim is worth considering now. If you need more memory, want Copilot+ features, or care about real-world noise, wait for reviews and for a 32GB configuration to appear in the store. You don't have to decide yet: nothing ships internationally until late October, so reviews may arrive before your unit would.
- Treat the memory as permanent. The LPDDR5X-7500 is soldered, and the U.S. store currently lists only 16GB configurations.
- Storage can be expanded. There are two M.2 2280 PCIe 4.0 x4 slots, with a manufacturer-stated maximum of 8TB total.
- For 4K at 120Hz, connect through DisplayPort 1.4 or USB4. Minisforum lists the HDMI 2.1 TMDS port at 4K/60Hz.
- Orders placed now carry an estimated late-October 2026 ship date, at $535 for 16GB/500GB or $599 for 16GB/1TB.
- Don't expect Copilot+ PC features. Minisforum advertises up to 10 TOPS of AI performance, but its own spec table lists the NPU as "N/A."
- Treat the 26dB idle and 40–45dB load figures as Minisforum's claims until someone tests them independently.
The UM780L Slim follows a familiar pattern in Minisforum's Slim line: a proven AMD laptop chip, given more power, in a case that mounts behind a monitor, at a price below newer silicon. The move to soldered LPDDR5X is what sets this model apart from earlier Slims. It brings extra bandwidth for the Radeon 780M at the cost of any later memory upgrade. The late-October shipping window is when independent tests should finally confirm or correct Minisforum's claims about noise, sustained power and performance.