Power Consumption and Temperatures

The MSI MAG B660M Mortar WiFi DDR4 uses two separate heatsinks for the VRM section. Each heatsink has multiple layers of large fins for better thermal dissipation with minimum airflow. Paired with 60 A power stages, the power delivery system may have difficulties with applications that require high power draw.



For temperature measurement, I use a Reed SD-947 4 channel Data Logging Thermometer paired with four Omega Engineering SA1 Self Adhesive Thermocouple probes. One probe directly touches the chipset and two are placed on select power stages. The last probe actively logs the ambient temperature.

For the MSI MAG B660M Mortar WiFi DDR4 one probe is placed along each bank of power stages. A probe is left out to log the ambient temperature. 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 i9-12900K left at stock configuration and voltage due to the inability to set anything higher. 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.


Because of the overclocking limitation, the VRM tests are split into three graphs for a better idea of normal use. Prime95 is brutal on the VRM during the torture test. Firstly, it caused an instant reboots after starting the test. The solution was to go into the BIOS and set the LCC to 8 and PWM Switching Frequency to 1000 Khz. This allowed for better transient response and stopped the instant reboot from happening.

Even though I was able to get Prime95 to run eventually, I terminated the test early to avoid heat-related damages from occurring. For reference, the reported power draw was roughly 277 watts.


Because Prime95 represents an unrealistic workload, the next best for real-world heavy application use is Cinebench R20. While this test passed, I would not use this motherboard without some airflow across the heatsinks during long encoding or 3D rendering.


Monitoring the temperatures during gaming yielded decent results considering the small heatsink size and inability to overclock the CPU. Any amount of airflow will drastically lower the temperatures and extend the power stages' life span.