Hot off the presses (figuratively)
A stress test is performed on the CPU to load the VRM power supply that supplies power to the CPU, but the verification method is based on the FF14 benchmark video (playback time 8 minutes, WQHD resolution, 60FPS, capacity 4.7GB) In Aviutl + x264, we performed two parallel encodings and continued to load over 30 minutes. At the end of this stress test, we will check the VRM power supply temperature using the FLIR ONE Pro thermography camera (review) that can be used on smartphones.
The basic results are as shown in the table above, and any B450 motherboard can be used as long as it is a Ryzen 7 3700X or Ryzen 3 3600, which has a CPU power consumption of about 90W with a core clock of TDP65W, PB2 & XFR2. I can do it.
The problem is when using Ryzen 9 3900X with TDP105W, ASUS TUF B450-PRO GAMING, MSI B450 TOMAHAWK MAX, and narrowly GIGABYTE B450 AORUS ELITE, ASRock B450 Steel Legend, the cooling condition of the VRM power supply is excellent It became evaluation.
First, about the ASUS TUF B450-PRO GAMING, even in a simple water-cooled CPU cooler environment where the VRM power circuit is not directly exposed to the wind, the core clock by PB2 & XFR2 will be used in the Ryzen 9 3900X, which has a CPU power consumption of about 150W in actual operation. Even when a load is applied, the VRM power supply temperature is 80 degrees or less. It was amazing performance that I couldn't think of as a 10,000-yen motherboard.
The next runner is MSI B450 TOMAHAWK. Compared to ASUS TUF B450-PRO GAMING, VRM power supply temperature is over 90 degrees with simple water cooling & Ryzen 9 3900X, but I think that VRM power supply is in the range where it can be operated just by passive air cooling.
ASRock B450 Steel Legend and GIGABYTE B450 AORUS ELITE were inferior to the above two.
As for the ASRock B450 Steel Legend, the VRM power supply temperature did not exceed 100 degrees within the range that can be confirmed by thermography, but if the load is continuously applied in an environment where the VRM power supply circuit is passively air-cooled, the VRM will take about several minutes. The phenomenon that the core clock is forcibly lowered due to overheating of the power supply, the so-called “phantom throttling”, was confirmed.
Even if a top-flow type air-cooled CPU cooler is used, the VRM power supply temperature cannot be lowered below 90 degrees unless the fan speed is increased.
Measured with a infrared camera , Ryzen 9 3900X VRM temps with Wraith Prism 1900RPM:
MSI B450 Tomahawk Max = 82.1°C
Gigabyte B450 Aorus Elite = 92.1°C
Asrock B450 Steel Legend = 96.0°C
Ryzen 9 3900X VRM temps with Corsair H150i AIO @ 1200RPM:
ASUS TUF B450-PRO GAMING = 79.2°C
MSI B450 Tomahawk Max = 94.2°C
Asrock B450 Steel Legend = 98.8°C
Gigabyte B450 Aorus Elite = 110.2°C
Surprising result to be honest , may have to do with measuring at front of the board (Tomahawk should be cooler than the TUF based on older testing)
edit: a refresher on the topology of the TUF Pro , it's Onsemi 4C10N x8 + 4C06N x8 (4 PWM phase) https://ru.gecid.com/mboard/asus_tuf..._gaming/?s=all