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GMKtec K12

GMKtecMini PC reference

GMKtec K12

GMKtec K12 combines AMD Ryzen 7 H 255 with integrated Radeon 780M for office multitasking, development and media work. Gaming and GPU-accelerated applications depend on their settings and driver support; the graphics specification alone is not a measured performance result. Replaceable SO-DIMM memory gives it a path for later RAM upgrades. OCuLink allows a separate compatible external GPU dock; connect or disconnect it only with the PC powered off.

Processor
AMD Ryzen 7 H 255
Graphics
Radeon 780M
Memory
32 GB
Storage
1 TB
Configuration being compared32 GB RAM · 1 TB SSDNew
US stores · USD

Prices across stores

MiniPC.guru compares retailer listings. Purchases are completed on the retailer’s website.

View price history
RetailerAvailabilityListed priceLast checkedRetailer website
In stock$919.99Lowest checkedView at GMKtec
In stock$919.99Sold by GMKtec一StoreLowest checkedView at Amazon

Availability reflects the latest store check. Shipping, tax, coupons and checkout totals are not included; confirm them at the store.

Specifications

Processor, graphics and installed memory/storage describe the selected configuration. Expansion limits and connectivity describe the model; optional hardware is identified separately. References are collected in About this data below.

Processor
AMD Ryzen 7 H 255
Graphics
Radeon 780M
Memory
32 GB
Storage
1 TB
Ports & displays
3 × USB-A 3.2 Gen 2 (10Gbps), 2 × USB-A 2.0; front USB-C 3.2 Gen 2 (data, DP, PD), rear USB4; HDMI 2.1, DisplayPort 1.4; OCuLink PCIe 4.0 ×4; 2 × 2.5GbE; 2 × 3.5mm audio jacks and DC input. Four display outputs are advertised. OCuLink is not hot-pluggable.
Ethernet, Wi-Fi & Bluetooth
Wi-Fi 6E (RZ616, up to 2.4Gbps); Bluetooth 5.2; Dual 2.5G Ethernet LAN (Realtek 8125BG) Link rates are theoretical, not measured throughput.
RAM & storage upgrades
2 × DDR5 SO-DIMM Slots; Dual-channel support; DDR5-5600 Memory; Supports up to 96GB. 3 × M.2 2280 PCIe 4.0 SSD Slots; 1 × PCIe 4.0 ×4 slot + 2 × PCIe 4.0 ×2 slots; Supports up to 24TB total storage
Power supply & power limits
Power supply / DC input rating: DC Power Adapter 19V / 6.32A, 120W. This is a supply rating, not measured wall-power consumption.
Dimensions & weight
154 × 151 × 73.6 mm; Approx. 920 g. Dimensions follow the manufacturer order; axes are not labeled.

What owners say

Four labs had this H 255 box — a chip one of them calls a rebadged 7840HS — and they heard three different machines. Notebookcheck found it loud even at idle, 35 dB(A) in a 24 dB(A) room; TechStage never saw more than 36 dB(A) at full load and mostly 28 to 32 without it; TechRadar called it silent in office use. The same spread shows in heat: settling at 78 °C in one stress test, an 83 °C peak falling to 60 °C over half an hour in another, never above 70 °C in a third that ran it at 65 W. It is larger and heavier than the K11, and the extra room buys three M.2 slots, one x4 and two x2. Idle draw is 11 to 13 W, load averages about 70 W, and the rear USB4 port can also power the machine. One review unit arrived with a loose screw on the board, and the fan cable is short enough to come unplugged when opening it. The case button changes the fan's colour, not its speed. Proxmox owners got graphics passthrough working, but one saw memory errors with mismatched sticks until he fitted a matched pair of 48 GB modules, and another reports unexplained crashes under Windows.

For whom
A roomy, well-connected mini PC for office work, development or a Proxmox host that needs three SSDs.
Not for
Anyone who needs it small or reliably silent at idle, and recent heavy games, which need low settings.

Our own summary of 5 published sources, reviewed Sep 23, 2026. We have not tested this Mini PC ourselves; the sources are listed under About this data.

Performance

4 sourced resultsFPS

A fixed game, build, benchmark scene, graphics preset and upscaling setting must be specified before publishing results.

Externally reported measurements. MiniPC.guru has not independently reproduced these tests.

43.5 FPSIndependent review

GMK NucBox K12 mini PC review: Bigger, but not necessarily faster

By Allen Ngo · Notebookcheck

Source published
Sep 26, 2025
Test performed
Not reported by source
Added to MiniPC.guru
Sep 23, 2026
Source reviewed
Sep 23, 2026
Tested hardware
AMD Ryzen 7 H 255, 8 cores / 16 threads, up to 4.9 GHz, Hawk Point-H (Zen 4), 54 W PL2 short burst and 54 W PL1 sustained · AMD Radeon 780M integrated, core 2550 MHz, driver 32.0.21025.10016 · 32 GB ADATA DDR5-5600, dual channel, timings 46-45-45-90 · Crucial P3 Plus CT1000P3PSSD8, 1024 GB, the drive shipped with the review unit
Software / version / OS
Cyberpunk 2077 · not reported by source: the review does not print the game build · Microsoft Windows 11 Pro
Power profile
Windows default Balanced mode, as the review's testing conditions state; 54 W PL2 short burst and 54 W PL1 sustained as printed in the specification table
Test conditions
1920x1080, Low preset, FSR off, printed in the row itself. Scene: Notebookcheck's published methodology says it uses a game's built-in benchmark where a representative one exists and CapFrameX otherwise, at https://www.notebookcheck.net/How-does-Notebookcheck-test-laptops-and-smartphones-A-behind-the-scenes-look-into-our-review-process.15394.0.html; this review does not restate which applied to Cyberpunk 2077, which does carry a built-in benchmark. Average 43.5 FPS, minimum 37.6, 1 per cent low 35.5

Editorial review checks the source and documentation; it does not certify the measurement or mean we tested the device ourselves.

33.9 FPSIndependent review

GMK NucBox K12 mini PC review: Bigger, but not necessarily faster

By Allen Ngo · Notebookcheck

Source published
Sep 26, 2025
Test performed
Not reported by source
Added to MiniPC.guru
Sep 23, 2026
Source reviewed
Sep 23, 2026
Tested hardware
AMD Ryzen 7 H 255, 8 cores / 16 threads, up to 4.9 GHz, Hawk Point-H (Zen 4), 54 W PL2 short burst and 54 W PL1 sustained · AMD Radeon 780M integrated, core 2550 MHz, driver 32.0.21025.10016 · 32 GB ADATA DDR5-5600, dual channel, timings 46-45-45-90 · Crucial P3 Plus CT1000P3PSSD8, 1024 GB, the drive shipped with the review unit
Software / version / OS
Cyberpunk 2077 · not reported by source: the review does not print the game build · Microsoft Windows 11 Pro
Power profile
Windows default Balanced mode, as the review's testing conditions state; 54 W PL2 short burst and 54 W PL1 sustained as printed in the specification table
Test conditions
1920x1080, Medium preset, FSR off, printed in the row itself. Scene: Notebookcheck's published methodology says it uses a game's built-in benchmark where a representative one exists and CapFrameX otherwise, at https://www.notebookcheck.net/How-does-Notebookcheck-test-laptops-and-smartphones-A-behind-the-scenes-look-into-our-review-process.15394.0.html; this review does not restate which applied to Cyberpunk 2077, which does carry a built-in benchmark. Average 33.9 FPS, minimum 29.5, 1 per cent low 20.2

Editorial review checks the source and documentation; it does not certify the measurement or mean we tested the device ourselves.

27.1 FPSIndependent review

GMK NucBox K12 mini PC review: Bigger, but not necessarily faster

By Allen Ngo · Notebookcheck

Source published
Sep 26, 2025
Test performed
Not reported by source
Added to MiniPC.guru
Sep 23, 2026
Source reviewed
Sep 23, 2026
Tested hardware
AMD Ryzen 7 H 255, 8 cores / 16 threads, up to 4.9 GHz, Hawk Point-H (Zen 4), 54 W PL2 short burst and 54 W PL1 sustained · AMD Radeon 780M integrated, core 2550 MHz, driver 32.0.21025.10016 · 32 GB ADATA DDR5-5600, dual channel, timings 46-45-45-90 · Crucial P3 Plus CT1000P3PSSD8, 1024 GB, the drive shipped with the review unit
Software / version / OS
Cyberpunk 2077 · not reported by source: the review does not print the game build · Microsoft Windows 11 Pro
Power profile
Windows default Balanced mode, as the review's testing conditions state; 54 W PL2 short burst and 54 W PL1 sustained as printed in the specification table
Test conditions
1920x1080, High preset, FSR off, printed in the row itself. Scene: Notebookcheck's published methodology says it uses a game's built-in benchmark where a representative one exists and CapFrameX otherwise, at https://www.notebookcheck.net/How-does-Notebookcheck-test-laptops-and-smartphones-A-behind-the-scenes-look-into-our-review-process.15394.0.html; this review does not restate which applied to Cyberpunk 2077, which does carry a built-in benchmark. Average 27.1 FPS, minimum 23.1, 1 per cent low 20.3

Editorial review checks the source and documentation; it does not certify the measurement or mean we tested the device ourselves.

23.6 FPSIndependent review

GMK NucBox K12 mini PC review: Bigger, but not necessarily faster

By Allen Ngo · Notebookcheck

Source published
Sep 26, 2025
Test performed
Not reported by source
Added to MiniPC.guru
Sep 23, 2026
Source reviewed
Sep 23, 2026
Tested hardware
AMD Ryzen 7 H 255, 8 cores / 16 threads, up to 4.9 GHz, Hawk Point-H (Zen 4), 54 W PL2 short burst and 54 W PL1 sustained · AMD Radeon 780M integrated, core 2550 MHz, driver 32.0.21025.10016 · 32 GB ADATA DDR5-5600, dual channel, timings 46-45-45-90 · Crucial P3 Plus CT1000P3PSSD8, 1024 GB, the drive shipped with the review unit
Software / version / OS
Cyberpunk 2077 · not reported by source: the review does not print the game build · Microsoft Windows 11 Pro
Power profile
Windows default Balanced mode, as the review's testing conditions state; 54 W PL2 short burst and 54 W PL1 sustained as printed in the specification table
Test conditions
1920x1080, Ultra preset, FSR off, printed in the row itself (the review prints a separate Ultra row with FSR2 on, 30 FPS, not used here). Scene: Notebookcheck's published methodology says it uses a game's built-in benchmark where a representative one exists and CapFrameX otherwise, at https://www.notebookcheck.net/How-does-Notebookcheck-test-laptops-and-smartphones-A-behind-the-scenes-look-into-our-review-process.15394.0.html; this review does not restate which applied to Cyberpunk 2077, which does carry a built-in benchmark. Average 23.6 FPS, minimum 19.9, 1 per cent low 16.3

Editorial review checks the source and documentation; it does not certify the measurement or mean we tested the device ourselves.

Price history

GMKtec K12 · 32 GB RAM · 1 TB SSD

Loading checks…

New condition · US stores · USD · Selected configuration only. Prices exclude shipping and tax. Each price stays on the chart until that listing's next check, for at most 36 hours, the same window the store prices use. Out-of-stock, failed and missing checks leave gaps.

About this data7 references

Specs and any benchmark results come from the sources below. We haven't tested this Mini PC ourselves.

Sources

  1. GMKtec K12 — manufacturer specifications ↗
    • Manufacturer / specification source
    • Ports & displays · Reviewed Sep 15, 2026
    • Ethernet, Wi-Fi & Bluetooth · Reviewed Sep 15, 2026
    • RAM & storage upgrades · Reviewed Sep 15, 2026
    • Power supply & power limits · Reviewed Sep 15, 2026
    • Dimensions & weight · Reviewed Sep 15, 2026
  2. Selected configuration ↗
    • Selected configuration
  3. GMK NucBox K12 mini PC review: Bigger, but not necessarily faster ↗
    • External benchmark · Reviewed Sep 23, 2026
    • Owner review source · Reviewed Sep 23, 2026
  4. GMKtec NucBox K12 mini PC review ↗
    • Owner review source · Reviewed Sep 23, 2026
  5. GMKtec K12 "AMD Ryzen 7 H 255" Mini PC Review - Strong Specs & IO For Just $409 US ↗
    • Owner review source · Reviewed Sep 23, 2026
  6. Starker Mini-PC mit Ryzen 7, 32 GB RAM & USB4: GMKtec Nucbox K12 im Test ↗
    • Owner review source · Reviewed Sep 23, 2026
  7. GMKTEC K12 | Ryzen 7 H 255 | Problem with IGPU ↗
    • Owner review source · Reviewed Sep 23, 2026

Related models

Models with related processors, graphics or use cases. Check each model’s specifications and configurations before comparing.

Beelink SER9 MAX (H 255)AMD Ryzen 7 H 255Beelink SER9 Pro (H 255)AMD Ryzen 7 H 255Beelink SER9 MAX (H 260)AMD Ryzen 7 H 260GEEKOM A7 (7940HS)AMD Ryzen 9 7940HS