VRM Overview

Everything was going well till we got around to testing the VRMs, as you can see, all was not well 10 minutes into our full load stress test with our Ryzen 9 9950X and the 8+2+2 power delivery's temperatures. Again, this isn't a realistic scenario for a board in this price range, but it's our standard test so it's important to compare it to the competition, even if it's under extreme conditions this board won't face when paired with a CPU with half the cores. Temperatures were already above 70°C by the six-minute mark and shortly after 12 minutes, were approaching 90°C. At this time, the rear of the board was so hot that some of our other thermistor probes actually lost adhesion to the PCB, but one managed to stay in place to record a final temperature of just over 92°C, with the software backing this up with its own reading of 93°C.


Despite this, the difference between pre- and post-stress test Cinebench scores was less than 10 points so it's unlikely there will be any performance throttling elsewhere except if conditions were warmer and more extreme than our stress test. However, running VRMs at these temperatures for long periods regularly won't end well in the longer term. This might have been improved by removing the plastic shroud on the main VRM heatsink and allowing it to breathe. As you can see above, it does cover a large area of the heatsink below.


The heatsinks themselves are also relatively small, but do at least have fins to boost surface area. Any local airflow from top-down coolers or AIO liquid coolers with VRM fans would likely see much better temperatures, as would decent airflow within a case.


All 10 power stages feeding vCore and SOC are Onsemi NCP 302155R rated at 60 A, with the board switching to OnsemiNTMFS4C10N 46 A stages for MISC.


We have two PWM controllers on the Gigabyte B850 Eagle WiFi7 Ice, both from Richtek in the form of the RT3678BE and RT3672EE.