GMKtec NucBox K12 Mini PC AMD Ryzen 7 H 255/ 32GB/ 1TB SSD/ Win 11 Pro
PRODUCT DESCRIPTION
GMKtec NucBox K12 Mini PC, AMD Ryzen 7 H 255 / 32 GB DDR5 / 1 TB SSD (GM5015) - 3 Years Warranty, Singapore Local Warranty
The serviceable one: upgradeable DDR5, three M.2 slots and OCuLink
The NucBox K12 is the machine in this range built to be worked on. Where the EVO models solder their memory, the K12 uses two standard DDR5 SO-DIMM slots that GMKtec publishes to 128 GB, and it fits three M.2 2280 slots rather than the usual two - GMKtec rates the trio to 24 TB. Add an OCuLink PCIe Gen4 x4 port for an external GPU and dual 2.5 Gigabit Ethernet, and it covers workstation, home-lab and network-appliance duty from a 154 x 151 x 73.6 mm box. It is the sensible choice when a three-year refresh cycle meets a workload that grows.
Read this first: the K12 has no NPU
AMD's specification page for the Ryzen 7 H 255 lists no dedicated NPU or AI engine, and GMKtec publishes no AI TOPS figure for this model. The K12 is a Zen 4 workstation-class mini PC, not an AI PC - it will not accelerate Copilot+ features or local model inference the way the EVO-X1, EVO-X1 Pro, EVO-T2S or EVO-X2 in our range do. We state this plainly because "NucBox" and "EVO" sit side by side in the same catalogue and the difference is not obvious from the model name. If on-device AI is what you are buying for, this is not the machine; if upgradeable memory, storage capacity and expansion are what you need, it is the best value here.
What this exact configuration is
GMKtec publishes the K12 as a barebone unit and as a populated 32 GB / 1 TB build, with a choice of US, EU, UK or AU power plug. This listing is the populated 32 GB / 1 TB build as recorded on the distributor build sheet for item code GM5015, EAN 6972570963945 - it ships with memory, storage and Windows 11 Professional installed, not as a barebone. The build sheet records the chassis as Cool Gray at 154 x 151 x 73.6 mm and 910 g, and the supplied adapter as 19V / 6.32A (120 W); GMKtec's own product page states none of those, which is why we cite the build sheet for them.
Where the sources differ: the 70 W figure, and the storage slots
AMD publishes a default TDP of 45 W and a configurable range of 35-54 W for the Ryzen 7 H 255. The distributor build sheet records 35-70 W and GMKtec publishes a flat 70 W. The 70 W ceiling is therefore GMKtec's platform tuning - supported by its "Silent VC" vapour-chamber cooling - rather than an AMD specification, and we print all three readings rather than reconciling them. Separately, GMKtec is the more specific source on storage: it publishes the three M.2 slots as two PCIe 4.0 x2 and one PCIe 4.0 x4. That matters - two of the three slots run at half width, so put your fastest drive in the x4 slot. The build sheet says only "3 x M.2 2280 PCIe" and does not distinguish them.
Warranty: three years here, one year from GMKtec
GMKtec's own store publishes a "1-Year Warranty" with a "Hassle-free 7-Day Return" for this product. The distributor build sheet for GM5015 records 3 Years. This unit is sold on the local distributor's three-year Singapore warranty rather than GMKtec's international one-year term. The build sheet records the term but not the service type, so this page does not state onsite, carry-in or return-to-base. Please ask us to confirm the service type and the claim process in writing before you order.
Why this page separates its sources
AMD's product page is the authority on the processor. GMKtec's product page is the authority on the system platform - cooling, storage topology, display output, expansion. The distributor build sheet is the only source describing this one SKU. The three are kept in separate tables below so you can see where each figure comes from. Where they disagree we print every reading and say so, and where none of them states a figure we write "not stated" rather than estimating it.
GMKtec NucBox K12 Datasheet - Technical Specifications
General
| GMKtec official product name | GMKtec K12 AMD Ryzen 7 H 255 Mini PC |
| Distributor item code | GM5015 |
| Our SKU on this listing | GM5015 |
| EAN | 6972570963945 |
| Form factor | Compact mini PC desktop |
| AI acceleration | None. AMD lists no NPU or AI engine for this processor, and GMKtec publishes no TOPS figure for this model. This is not an AI PC. |
| Warranty as sold | 3 Years, Singapore local warranty. Service type not stated on the build sheet - please ask us to confirm before ordering. |
| Manufacturer's own published warranty | GMKtec publishes "1-Year Warranty" with "Hassle-free 7-Day Return" on its own store. The three-year term on this listing is the local distributor's, not GMKtec's. |
| Configurations GMKtec publishes | Barebone (no memory, storage or OS), or populated 32 GB / 1 TB. Each with a choice of US, EU, UK or AU power plug. This listing is the populated build. |
This Configuration - From the Distributor Build Sheet for GM5015
| Processor | AMD Ryzen 7 H 255, 24 MB cache, up to 4.9 GHz, 8 cores / 16 threads. The 24 MB figure is the combined total of AMD's published 8 MB L2 and 16 MB L3. |
| TDP as recorded | 35-70 W. Above AMD's published 35-54 W cTDP range - see the note above the tables. |
| Memory | 32 GB DDR5 SO-DIMM (2 x 16 GB), upgradeable to 128 GB |
| Storage | 1 TB M.2 PCIe SSD. 3 x M.2 2280 PCIe slots. The build sheet does not distinguish slot widths - GMKtec does; see below. |
| Graphics | AMD Radeon 780M Graphics |
| Wireless | Dual Band Wi-Fi 6E; Bluetooth 5.2 - agrees with GMKtec |
| Networking | Dual Gigabit LAN (2.5G RJ45) - agrees with GMKtec |
| Audio | High Definition Audio |
| Ports | 2 x USB 2.0; 3 x USB 3.2; 2 x USB-C (power delivery / DisplayPort / data); 2 x Gigabit LAN (2.5G RJ45); 1 x HDMI 2.1; 1 x DisplayPort 1.4; 2 x 3.5 mm audio; 1 x OCuLink PCIe Gen4x4. Note: the build sheet describes both Type-C ports generically; GMKtec publishes one of them as USB4. |
| Power adapter | 19V / 6.32A (120 W) |
| Dimensions | 154 (W) x 151 (D) x 73.6 (H) mm |
| Weight | 910 g |
| Chassis colour | Cool Gray |
| Operating system | Windows 11 Professional |
| Warranty term on the build sheet | 3 Years |
Processor Platform - From AMD
| AMD model name | AMD Ryzen 7 H 255 (Ryzen 200 Series, mobile) |
| Source note | AMD's English-language product page for this part returns a 404 at the time of writing; the figures below are taken from AMD's own China-region product page for the same part, linked in Datasheet & Downloads. We flag this because it is not AMD's primary English source. |
| Cores and threads | 8 cores, 16 threads (SMT) |
| Architecture | Zen 4, TSMC 4 nm FinFET |
| Clock speeds | Base clock 3.8 GHz; max boost up to 4.9 GHz |
| Cache | L2 cache 8 MB; L3 cache 16 MB (24 MB combined) |
| TDP | Default TDP 45 W. AMD Configurable TDP (cTDP) 35-54 W. Both GMKtec and the build sheet cite a 70 W ceiling, above this range. |
| Integrated graphics | AMD Radeon 780M, 12 graphics cores, 2600 MHz |
| NPU / AI engine | Not listed. AMD publishes no NPU or AI TOPS figure for this processor. |
| Memory support | DDR5 and LPDDR5X. Max speeds DDR5-5600 and LPDDR5x-7500. Max capacity 256 GB across 2 memory channels. Note that this is the processor's ceiling - GMKtec publishes 128 GB as the K12's platform maximum. |
| PCIe | PCIe 4.0, 20 native lanes - which is what allows three M.2 slots plus an OCuLink port on one platform |
System Platform - From GMKtec
| Processor, GMKtec's wording | "AMD Ryzen 7 H 255" with "8 Cores, 16 Threads, Max 4.9GHz", base clock 3.8 GHz, TDP 70 W |
| Graphics, GMKtec's wording | "AMD Radeon 780M" with "12 cores running at 2600 MHz" - matches AMD |
| Memory, GMKtec's wording | "Dual DDR5 5600MHz" with "2*SO-DIMM MAX 128GB", user-upgradeable |
| Storage topology | Three M.2 2280 slots: two PCIe 4.0 x2 and one PCIe 4.0 x4, supporting up to 24 TB total. Put your fastest drive in the x4 slot. |
| Expansion | "OCulink Port" (PCIe Gen4 x4), which GMKtec states supports an external RTX 4060-class GPU |
| Display output | "Quad Screens Display" via "HDMI 2.1 + DP 1.4 + USB 4 + Type-C", supporting "Up to 8K@120Hz" |
| Networking | "Dual 2.5G Ethernet Ports"; Wi-Fi 6E rated at 2.4 Gbps; Bluetooth 5.2 |
| Cooling | "Silent VC cooling" with a "vapor chamber thermal design" and "dual 3D surround air intakes" |
| AI performance | Not stated. GMKtec publishes no TOPS figure for this model. |
| Dimensions, weight, colour, OS | Not stated on GMKtec's product page. See the build sheet table above. |
Compatibility & Fit
What this machine works with
| Memory upgrade | Yes - this is the model's main advantage. Two standard DDR5 SO-DIMM slots, shipped with 2 x 16 GB, upgradeable to 128 GB per GMKtec. AMD's processor ceiling is 256 GB across two channels, so the 128 GB figure is GMKtec's platform limit. Standard SO-DIMM modules fit - not LPCAMM2, and not soldered. |
| Storage upgrade | Three M.2 2280 slots, up to 24 TB total per GMKtec. Two run at PCIe 4.0 x2 and one at PCIe 4.0 x4. One slot carries the supplied 1 TB drive, leaving two free. If you are adding a fast drive, check which slot you are using. |
| External GPU over OCuLink | OCuLink PCIe Gen4 x4 is fitted, per both sources. GMKtec states it supports an external RTX 4060-class GPU. The dock, the graphics card and a power supply for the card are all separate purchases and are not included. |
| Displays | GMKtec publishes quad-display output at up to 8K@120Hz over HDMI 2.1, DisplayPort 1.4, USB4 and Type-C. The build sheet lists the same ports but states no display count or resolution ceiling, so both figures are GMKtec's alone. |
| Networking | Two 2.5 Gigabit Ethernet ports, agreed by both sources - so segmentation, link aggregation, pfSense or OPNsense firewall roles are all possible. Wi-Fi 6E and Bluetooth 5.2 are also agreed. |
| No NPU | This platform has no AI accelerator. For Copilot+ class features or local model inference, look at the EVO-X1, EVO-X1 Pro, EVO-T2S or EVO-X2 instead. |
| Power | Supplied 19V / 6.32A (120 W) adapter per the build sheet, against a 70 W platform ceiling - so there is headroom for bus-powered peripherals. |
| Security lock | The build sheet does not list a Kensington slot for this model, unlike several others in the range. If a lock point is required, please ask us to confirm before ordering. |
Package Contents & Ordering Information
Neither GMKtec's product page nor the distributor build sheet for GM5015 publishes an itemised box-contents list. The build sheet records the power adapter; everything else below ships with the product as a matter of normal practice rather than as a published specification. If a bundled item is essential to your order, please confirm it with us in writing before you buy.
- The GMKtec NucBox K12 mini PC itself, with memory, storage and Windows 11 Pro already installed
- 19V / 6.32A (120 W) power adapter - recorded on the build sheet for this item code
- Power cord, VESA mounting hardware and documentation - not itemised by either source; please confirm with us if required
- An OCuLink dock and external GPU are not included
Note that GMKtec also sells the K12 as a barebone unit with no memory, storage or operating system. This listing is not that - it is the populated build.
Related GMKtec configurations we carry
| GM5013 | EVO-X2 - Ryzen AI Max+ 395 / 128 GB / 2 TB - S$5,520.00 - 3 Years. 126 TOPS and 128 GB unified memory; soldered, no OCuLink, single 2.5G LAN. |
| GM5026 | EVO-T2S - Intel Core Ultra X7 358H / 64 GB / 1 TB - S$3,099.60 - 3 Years. 180 TOPS, 10G LAN and OCuLink. |
| GM5027 | EVO-X1 Pro - Ryzen AI 9 HX 470 / 64 GB / 1 TB - S$2,082.00 - 3 Years. 86 TOPS, OCuLink, dual 2.5G LAN; memory soldered. |
| GM5009 | EVO-X1 - Ryzen AI 9 HX 370 / 32 GB / 1 TB - S$1,742.40 - 3 Years. 80 TOPS, OCuLink, dual 2.5G LAN; memory soldered. |
| GM5015 (this listing) | NucBox K12 - Ryzen 7 H 255 / 32 GB DDR5 / 1 TB - S$1,365.60 - 3 Years. No NPU, but upgradeable memory to 128 GB and three M.2 slots. |
Item codes link to the matching listing where we carry it. Configurations, prices and availability change without notice; please confirm with us before ordering.
Datasheet & Downloads
GMKtec does not publish a downloadable per-SKU datasheet for the K12, so there is no single PDF describing this one configuration. The links below are the manufacturer sources behind the figures on this page.
- GMKtec - K12 Mini PC product page (source of the System Platform figures)
- AMD - Ryzen 7 H 255 product specifications (AMD's China-region page; the English page returns a 404 at the time of writing)
- GMKtec - Drivers & Software
- GMKtec - Warranty, Returns & Refund (GMKtec's own one-year term)
Warranty on this listing is the local distributor's three-year term, registered against the unit. GMKtec's own published term is one year. We are happy to confirm the local entitlement and the claim process for you before delivery.
Frequently Asked Questions - GMKtec NucBox K12
Does the K12 have an NPU for AI work?
No. AMD's specification page for the Ryzen 7 H 255 lists no NPU or AI engine, and GMKtec publishes no TOPS figure for this model. It is a Zen 4 workstation-class mini PC. If you need on-device AI acceleration - Copilot+ features, local model inference - choose one of the EVO models instead: the EVO-X1 at 80 TOPS, EVO-X1 Pro at 86 TOPS, EVO-T2S at 180 TOPS or EVO-X2 at 126 TOPS.
Can the memory be upgraded later?
Yes, and this is the K12's main advantage over the EVO range. It uses two standard DDR5 SO-DIMM slots, shipped with 2 x 16 GB, which GMKtec publishes as upgradeable to 128 GB. AMD's processor ceiling is higher still at 256 GB, so 128 GB is GMKtec's platform limit rather than the silicon's. Ordinary SO-DIMM modules fit - existing stock will work.
Are all three M.2 slots the same speed?
No. GMKtec publishes two of the three as PCIe 4.0 x2 and one as PCIe 4.0 x4. The x4 slot has twice the bandwidth, so put your fastest or most-used drive there. The distributor build sheet does not distinguish the slots at all, which is why we cite GMKtec for this. Total capacity across the three is published at 24 TB.
Why does GMKtec say 70 W when AMD publishes a 54 W ceiling?
AMD publishes a default TDP of 45 W and a configurable range of 35-54 W for the Ryzen 7 H 255. GMKtec publishes a flat 70 W and the distributor build sheet records 35-70 W. The 70 W figure is GMKtec's platform tuning, supported by its "Silent VC" vapour-chamber cooling design, rather than an AMD specification. We print all three readings rather than reconciling them.
Is this the barebone version?
No. GMKtec sells the K12 both as a barebone unit - no memory, no storage, no operating system - and as a populated build. This listing is the populated 32 GB / 1 TB build with Windows 11 Professional installed, per the distributor build sheet for GM5015.
What can I connect to the OCuLink port?
An OCuLink external GPU dock. Both sources record the port as PCIe Gen4 x4, and GMKtec states it supports an external RTX 4060-class card. OCuLink carries a direct PCIe link rather than tunnelling over Thunderbolt, which is why it is faster for GPU work. The dock, the graphics card and a power supply for the card are all separate purchases.
How many displays will it drive?
GMKtec publishes "Quad Screens Display" at up to 8K@120Hz over HDMI 2.1, DisplayPort 1.4, USB4 and Type-C. The distributor build sheet lists the same video-capable ports but states no display count or resolution ceiling, so both figures are GMKtec's alone. Note also that the build sheet describes both Type-C ports generically while GMKtec publishes one of them as USB4 - ask us to confirm if a USB4 dock is central to your setup.
What warranty does it actually come with?
Three years, per the distributor build sheet for item code GM5015 - a local Singapore term, not GMKtec's international one. GMKtec's own store publishes a one-year warranty with a seven-day return window. The build sheet records the three-year term but not the service type (onsite, carry-in or return-to-base), so please ask us to confirm the service type and the claim process in writing before you order.
