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GMKTech K8 Plus - PTM7950 & Perf at various DDR5 speeds! Mini PC

Jul 30, 2025

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GMKTech K8 Plus: Performance Testing with PTM7950 and Various DDR5 Speeds

Boost your GMKTech K8 Plus mini-PC performance! We test DDR5 RAM and PTM7950 thermal paste upgrades.

This review examines the GMKTech K8 Plus mini-PC with an 8845HS processor, featuring dual 2.5GbE ports, an Oculink port, and USB 4. Special attention is paid to the impact of DDR5 RAM speed and replacing the thermal paste with PTM 7950 on the device's performance and noise levels.

The Impact of RAM Speed on Performance

To assess the impact of RAM speed on performance, tests were conducted using two configurations: 4800 MHz CL (timings not specified) and 5600 MHz with two latency options—CL46 and CL40. Testing was performed using the Time Spy (3D Score) and Final Fantasy Benchmark benchmarks.

Test Results:

  • Time Spy (3D Score):

    • 4800 MHz: 2677 points.
    • 5600 MHz CL46: 2889 points (an increase of ~8% compared to 4800 MHz).
    • 5600 MHz CL40: A performance increase of an additional 1.21% compared to CL46.

  • Final Fantasy Benchmark:

    • 4800 MHz: 3649 points.
    • 5600 MHz CL46: A performance increase of 5.59% compared to 4800 MHz.
    • 5600 MHz CL40: A performance increase of an additional 2.5% compared to CL46.

Overall, the transition from 4800 MHz to 5600 MHz provided a performance boost of around 8-10% in Time Spy and approximately 8% in Final Fantasy. The difference between CL46 and CL40 at 5600 MHz was less significant but noticeable. It is noted that a 10% performance increase is comparable to the difference between i5 and i7 processors in some scenarios.

Replacing Thermal Paste with PTM 7950

The second stage of optimization involved replacing the stock thermal paste with the PTM 7950 thermal interface. The procedure included disassembling the mini-PC case, removing the cooling system, and cleaning the surfaces of the processor and heatsink.

Replacement Process:

  1. Remove the top cover of the case by rotating it 45 degrees.
  2. Disconnect the fan.
  3. Remove the rear part of the case.
  4. Unscrew the four screws securing the cooling system.
  5. Carefully remove the cooling system.
  6. Clean the processor and heatsink of old thermal paste using isopropyl alcohol.
  7. Apply PTM 7950 thermal paste, cut to the size of the chip.
  8. Reassemble the cooling system and the case.

Test Results After Thermal Paste Replacement

To assess the effectiveness of the thermal paste replacement, a 100% load test was conducted using FurMark before and after installing PTM 7950.

Key Observations:

  • CPU Temperature: With PTM 7950, the CPU temperature significantly decreased. In the stock configuration, the temperature reached 90°C and above, causing throttling. After replacing the thermal paste, the maximum temperature did not exceed 82-83°C, which is within the safe zone for the chip.
  • Fan Speed: The reduction in temperature allowed for lower fan speeds. In the stock configuration, the CPU fan reached 3500 RPM, whereas with PTM 7950, the maximum speed was around 3300 RPM. The power supply fan also operated at lower speeds. This resulted in a reduction in the overall noise level of the device.
  • CPU Package Power: Thanks to more efficient cooling, the CPU with PTM 7950 had more "headroom" and could maintain higher power consumption levels without throttling. It is noted that the thermal paste replacement itself does not provide a performance boost, as the device is not subject to severe throttling, but it allows the system to operate more stably and quietly.

Выводы и дальнейшие перспективы

GMKTech K8 Plus демонстрирует значительный потенциал для оптимизации. Выбор более быстрой оперативной памяти DDR5 (5600 МГц CL40) может увеличить производительность на 8-10%. Замена штатной термопасты на PTM 7950 существенно снижает рабочие температуры процессора, что, в свою очередь, уменьшает скорость вращения вентиляторов и уровень шума, делая устройство более комфортным в использовании.

В качестве дальнейших шагов для улучшения производительности рассматривается возможность модификации BIOS для поддержки более быстрой оперативной памяти (6200-6400 МГц), что может дополнительно повысить производительность графического процессора. Устройство также позиционируется как отличная основа для создания eGPU-систем.

Introduction and Testing Objectives

Overview of the GMKTech K8 Plus mini-PC, its key features (8845HS processor, Oculink, USB4), and testing objectives: comparing performance with different DDR5 RAM and replacing thermal paste with PTM7950 for improved cooling and reduced noise.

  • Model: GMKTech K8 Plus.
  • Processor: 8845HS.
  • Features: Oculink, USB4.
  • Objective: Compare performance with 4800 MHz RAM vs 5600 MHz (CL46/CL40).
  • Objective: Replace thermal paste with PTM7950 for improved cooling and reduced noise.

RAM Replacement

Demonstration of the process of replacing RAM in the GMKTech K8 Plus. It shows how to remove the top cover and replace the existing 5600 MHz CL46 memory with new 5600 MHz CL40 memory, focusing on the expected impact on performance.

  • Process of removing the top cover of the mini-PC.
  • Replacing DDR5 RAM.
  • Using G.Skill Ripjaws 5600 MHz CL40 memory.
  • Comparison with previous 5600 MHz CL46 and 4800 MHz memory.

RAM Performance Testing

Performance testing results with different RAM. In Time Spy 3D, increasing the speed from 4800 to 5600 MHz yielded an 8% increase, and switching from CL46 to CL40 added another 1.21%. In Final Fantasy XV, the gains were 5.59% and 2.5% respectively. It is noted that the difference between 4800 and 5600 MHz is more significant than between CL46 and CL40.

  • Time Spy 3D Benchmark: 4800 MHz - 2677, 5600 MHz CL46 - 2889 (+8%), 5600 MHz CL40 - +1.21% over CL46.
  • Final Fantasy XV Benchmark: 4800 MHz - 3649, 5600 MHz CL46 - +5.59%, 5600 MHz CL40 - +2.5% over CL46.
  • Overall performance increase: ~9-10% in Time Spy, ~8% in Final Fantasy.
  • Importance of RAM speed choice (5600 MHz preferred over 4800 MHz).

Replacing Thermal Paste with PTM7950

The process of replacing thermal paste with PTM7950 in GMKTech K8 Plus. Shows removal of the top case, disconnecting the fan, accessing the cooling system, cleaning off old thermal paste, and applying new PTM7950. Notes the presence of an evaporation chamber in the cooling system.

  • Disassembly of the top case.
  • Disconnecting the fan.
  • Accessing the cooling system.
  • Cleaning off old thermal paste (presumably of good quality).
  • Applying PTM7950 thermal paste.
  • Presence of an evaporation chamber in the cooling system.

Testing after thermal paste replacement

Testing results after replacing thermal paste. A 100% load test (Firmark) showed a significant decrease in CPU temperature (green line PTM7950 vs. red stock). Fan speeds (CPU and Power) also decreased, reducing noise. Power consumption remained the same, but the processor operated more stably, not reaching critical temperatures.

  • Firmark test (100% load) before and after thermal paste replacement.
  • Significant decrease in CPU temperature with PTM7950.
  • Reduced CPU fan speed (from 3500 to ~3300 RPM) and power fan speed.
  • Reduced noise level.
  • Stable CPU operation without throttling (temperature did not exceed ~83°C).
  • Power consumption remained the same, but the processor had a greater temperature margin.

Conclusion and Future Possibilities

Final conclusions on GMKTech K8 Plus. An 8-10% performance improvement was achieved by selecting the right RAM kit. Replacing the thermal paste with PTM7950 reduced temperature and noise. The author suggests the possibility of further optimization through a modified BIOS to use faster memory (6200-6400 MHz).

  • 8-10% performance improvement due to RAM choice.
  • PTM7950 reduces temperature and noise.
  • Possibility of further optimization via BIOS (e.g., for 6200-6400 MHz RAM).
  • GMKTech K8 Plus is a great base for eGPU.