Power Consumption and Temperatures

The ASRock Z690 Phantom Gaming-ITX/TB4 uses two heatsinks connected via a heatpipe. Due to the limited surface area, there isn't much room to expand in size. The backplate mainly acts as PCB support, but also has two thermal pads behind the two VRM sections to provide extra passive cooling.


Because of the smaller size, ASRock implemented a tiny fan to help combat thermals. By placing the fan directly over the heatpipe, ASRock engineers are hoping it will suffice. However, it is poorly designed. With no spare space behind the fan or a surface with fins, this fan is not doing anything useful. Being that it is far away from the rear I/O shield, no air was felt coming out of the holes. I have seen better designs from ASRock. This is just a copy and paste job from the Z590 Phantom Gaming-ITX/TB4. While It may have worked on the last generation, it does not here.



For the ASRock Z690 Phantom Gaming-ITX/TB4, one probe is placed along each bank of power stages. A probe is left out to log the ambient temperature. For temperature measurement, I use a Reed SD-947 4 channel Data Logging Thermometer paired with four Omega Engineering SA1 Self Adhesive Thermocouple probes. All temperatures are presented as Delta-T normalized to 20°C, which is the measured temperature minus the ambient temperature plus 20°C. The end result accounts for variation in ambient temperature, including changes over the course of a test, while presenting the data as if the ambient were a steady 20°C for easy presentation. Additionally, there is direct airflow over the VRM for the first five minutes, after which the fan is removed. This gives an idea of what to expect with and without moderate case airflow.

Prime95 is used for maximum power consumption over a 30 minute period. For testing, I used an Intel Core i5-12600KF set to 5.0 GHz and locked at 1.35 V. Other tests are conducted with an Intel Core i9-12900K set to 5.0 GHz all-core and stock configurations. Temperatures are logged every second, and the two probes are then averaged for a cleaner presentation before subtracting the ambient to calculate the Delta-T. The results are charted below.


These VRM tests are split into multiple charts to give a wider understanding of the Z690 Phantom Gaming-ITX/TB4 cooling solution. Prime95 is in many ways designed to be a brutal torture test. It is a fairly unrealistic daily use case. That being said, without a direct fan placed on the VRM heatsinks, these power stages reach nearly 100°C. I already said this previously, but that internal fan utterly fails in providing any sort of additional cooling.


The next step was to take the current high-end CPU from Intel, which is the i9-12900K. This is a more realistic use case of an overclocked CPU that is strictly used outside gaming situations. Once again, it is toasty and needs a fan in the area to keep VRM temperatures in check.


Next up was to see how well it does without changing any default settings. This is completely running at stock. While the power draw may be in the 250-watt range, the VRM is capable of handling this load for long periods of time. However, it is outside my personal comfort zone.


The final test was to see how the VRM heatsink may fare in games. Even with a CPU overclock, I believe gaming would not cause much of a problem. The load isn't constant as Cyberpunk 2077 generally had the CPU clock frequency in the 3 GHz range, which moved up or down as the GPU load changed.