The MSI Cubi NUC AI+ 3MG harnesses Intel's Panther Lake to create a capable mini PC with a truly tiny footprint

Faster, smaller, more efficient – pick three. That's MSI's proposition for the Cubi NUC AI+ 3MG. With Intel's Lunar Lake generation making way for the new Panther Lake-H chips, MSI has been able to slash the Cubi down in size while boosting performance in the places that matter for business use. Lunchtime gamers might not be so happy – and I'll explain in more detail why later – but for everyone else, this is a big upgrade in a very small package.

MSI has shrunk the 3MG generation right down. Palm-sized might be stretching it a little, but it's not far off: this mini PC measures a few millimetres shy of a 12cm x 12cm square and stands 37.5mm tall.

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MSI sent us the top-end model, but naturally there are a variety of pre-built and barebones skus to consider. There are a trio of Panther Lake processors to choose from – the Core Ultra 5 322 (6 core, 6 threads, up to 4.4Ghz, 40+ TOPS), Core Ultra 7 355 (8 core, 8 threads, up to 4.7Ghz, 45+ TOPS) and the flagship Core Ultra 9 386H (16 core, 16 threads, up to 4.9Ghz, 50 TOPS).

IT departments with a healthy supply of DDR5 SODIMMs, M.2 2280 SSDs and spare Windows licenses can select one of the three barebones models which retail for around £460, £550 and £680. Pre-built models start at around £900 for the Ultra 5 322, 16GB DDR5 and 512GB SSD model, with the Ultra 7 355, 16GB, 1TB model pushing up to £1,099 and the Ultra 9 386H, 32GB, 1TB model topping out at £1,400. All ship with Windows 11 Pro.

The 3-year warranty is worth mentioning here, too. That's significantly longer than some rival devices, and if you buy via a B2B supplier you'll be able to upgrade to the Advanced Replacement scheme, which sends out a replacement device the instant your device is diagnosed as faulty.

MSI Cubi NUC AI+ 3MG: Design & connectivity

This compact matte black cuboid fits is nothing much to look at, but practicality is the priority here – it's compact, well connected, and you get tool-free access to the SSD and RAM. Turn the little fingerscrew, slide and pull the little tab, and the latch releases the metal base. It's very neat.

Most users won't need more than the 32GB of DDR5 memory that this review unit shipped with – but you can push it up to 128GB for very specific AI or mini server duties. And the ability to quickly slide in a new PCIe Gen 4 SSD may come in handy, too.

There's a good amount of connectivity here for the size. Up front, you get two USB-A ports – one full-speed 10Gbit port, one limited to USB 2.0 speeds – and a single 10Gbit USB-C port. There are two Thunderbolt 4 USB-C ports at the rear, and these support up to 98 watts of power delivery for compatible devices. The pair of 2.5GbE Ethernet ports is backed up by an MTK RZ717 chip, which provides Wi-Fi 7 and Bluetooth 5.4.

You can now connect up to four displays – up from the three on the previous generation – which is great for power users: the pair of HDMI 2.1 ports can be used alongside the pair of Thunderbolt 4 USB-C ports to power four 4K 60Hz displays. With two discrete Thunderbolt 4 controllers, you can daisy-chain two displays off of a single port and save the other for high-speed external drives or similar.

A single power input accommodates the 120-watt laptop-style power supply, but you don't have to use it – the unit also accepts up to 98 watts of power delivery from a compatible USB-C equipped hub or monitor. The maximum power delivery the MSI itself can generate is 15 watts, though, so it won't fast charge anything bigger than a phone or tablet.

There are compromises. For example, there is no SD card reader, no 3.5mm headphone output, and no rear-facing USB-A ports. It feels like MSI very much intends this mini PC to be used with a docking station – or a well-appointed USB-C monitor which can provide the missing USB and audio connections.

The combined power button and fingerprint reader on the front of the Cubi is rather ingenious – or at least it is, as long as you don't take advantage of the VESA mounting plate in the box. Reaching around the back of your monitor to log in would be marginally less than ideal. In fairness, MSI does supply a short extension cable with a light, plasticky power button backed with a sticky pad for this exact scenario, but you do lose the fingerprint login functionality. It's good to see that a discrete TPM chip comes as standard, though.

MSI Cubi NUC AI+ 3MG: Performance

The range-topping Intel Core Ultra 9 386H in the top-end Cubi 3MG model is significantly more powerful than the previous generation. It doubles the overall core count, taking the previous generation's four performance and four low-power cores and adding a further 8 efficiency cores. AI performance takes a big step forward as a result: Intel's NPU 5 architecture delivers 50 TOPS of AI compute in this high-end chip, a handful less in the slower variants. This combines with the CPU and GPU to generate 100 TOPS of compute. Impressive for a unit that fits in the palm of your hand.

Those upgrades have led to some sacrifices: GPU performance isn't a patch on the previous Lunar Lake generation. With a Mini PC of this size, something has to give. Instead, the Panther Lake generation slashes the GPU core count in half and settles for four of the new Battlemage Xe3 cores. That said, a little lunchtime gaming isn't entirely out of the question. The 3DMark results are similar to the last Lunar Lake generation, but I found that even demanding titles such as Arc Raiders played fine at 2,560 x 1,440 and lowest settings with XeSS Performance mode enabled, with framerates generally hovering between 40fps and 60fps.

This is all the more impressive when you consider that MSI has had to place some tight thermal limits on the Panther Lake chips to prevent the tiny chassis from overheating. The chip simply isn't allowed to boost to its maximum wattage, and sustained workloads are similarly restrained. The flipside here is that, even with sustained heavy gaming or multi-core workloads, the MSI is never excessively noisy. Heavy loads see the fans spin up to a steady white noise, but this is quite easy to ignore – and unlike some mini PCs it's never irritatingly shrill.

The tight power limits explain why the benchmark results aren't universally leaps and bounds ahead of previous-generation mobile chips. For instance, you'd expect the latest architecture to stretch its legs against the two-generations-old 16-core Core 9 Ultra 185H in the Geekom IT13 Max, but it actually performs similarly. This isn't the disappointment it sounds, however: the Geekom is almost twice the size, and it allows its fans to reach higher noise levels to give the chip more headroom.

Despite this, the MSI still gives a good showing as it pushes around 7% ahead in Geekbench 6's single core benchmark, with a result of 2,546, and even edges out a slim 3% lead in the multi-threaded tests with 13,486. Graphics performance drops behind, though, with the MSI falling 43% behind the Geekom. Again, though, even this loss speaks to the efficiency improvements for this generation: the Geekom's Meteor Lake GPU has double the number of GPU cores at its disposal.

MSI Cubi NUC AI+ 3MG: Is it worth it?

The Cubi NUC AI+ 3MG is a great example of a well-engineered mini PC. Some sensibly restrained power limits have allowed MSI to pack considerable capabilities into a tiny, quiet footprint, and the only real disappointment here is that you simply can't eke every last drop of performance from the platform. After all, there's only so much heat that a half-litre chassis can handle.

For many desks, though, a few compromises for quieter operation make a lot of sense. You get the upgradable RAM and SSD options from the older Meteor Lake generation, a big boost in AI compute power, and more than sufficient oomph to handle a wide range of day-to-day workloads. Suffice to say, the MSI Cubi NUC AI+ 3MG is a mini PC with big potential.

MSI Cubi NUC AI+ 3MG specifications