Power Delivery Thermal Analysis

One of the most requested elements of our motherboard reviews revolves around the power delivery and its componentry. Aside from the quality of the components and its capability for overclocking to push out higher clock speeds which in turn improves performance, is the thermal capability of the cooling solutions implemented by manufacturers. While almost always fine for users running processors at default settings, the cooling capability of the VRMs isn't something that users should worry too much about, but for those looking to squeeze out extra performance from the CPU via overclocking, this puts extra pressure on the power delivery and in turn, generates extra heat. This is why more premium models often include heatsinks on its models with better cooling designs, heftier chunks of metal, and in some cases, even with water blocks.

Testing Methodology

Our method of testing is going to focus on if the power delivery and its heatsink are effective at dissipating heat. We run an intensely heavy CPU workload for a prolonged method of time and apply an overclock which is deemed safe and at the maximum that the silicon on our AMD Ryzen 7 3700X processor allows. We then run the Prime95 with AVX2 enabled under a torture test for an hour at the maximum stable overclock we can, which puts insane pressure on the processor. We collect our data via three different methods which include the following:

  • Taking a thermal image from a birds-eye view after an hour with a Flir Pro thermal imaging camera
  • Securing two probes on to the rear of the PCB, right underneath CPU VCore section of the power delivery for better parity in case a probe reports a faulty reading
  • Taking a reading of the VRM temperature from the sensor reading within the HWInfo monitoring application


Two K-Type Thermal Probes attached to the rear of the power delivery on the ASUS Pro WS X570-Ace

The reason for using three different methods is that some sensors can read inaccurate temperatures, which can give very erratic results for users looking to gauge whether an overclock is too much pressure for the power delivery handle. With using a probe on the rear, it can also show the efficiency of the power stages and heatsinks as a wide margin between the probe and sensor temperature can show that the heatsink is dissipating heat and that the design is working, or that the internal sensor is massively wrong. To ensure our probe was accurate prior to testing, I personally binned 10 and selected the most accurate (within 1c of the actual temperature) for better parity in our testing.

For thermal image, we use a Flir One camera as it gives a good indication of where the heat is generated around the socket area, as some designs use different configurations and an evenly spread power delivery with good components will usually generate less heat. Manufacturers who use inefficient heatsinks and cheap out on power delivery components should run hotter than those who have invested. Of course, a $700 flagship motherboard is likely to outperform a cheaper $100 model under the same testing conditions, but it is still worth testing to see which vendors are doing things correctly.

Thermal Analysis Results


We measured 55.5°C on PCB between the CPU socket and power delivery

The ASUS Pro WS X570-Ace is running a 12-phase power delivery for the CPU VCore and a 2-phase setup for the SoC. This is controlled by an ASP1405I which is a rebadged International Rectifier IR35201 PWM controller which is operating in a 6+1 configuration. Cooling the power delivery is a good-sized aluminium heatsink with uniformed fins which when combined with good passive airflow, should prove effective. As ASUS is running the Pro WS X570-Ace power delivery power stages in a teamed mode as opposed to doublers, this should, in theory, make the power delivery cooler. Delivering power to the CPU is a single 8-pin 12 V ATX which is more than enough power for the current Ryzen 3000 processor line-up.


As we get more results, we will endeavour to update this chart when more models have been tested

Note - The ASRock B450 Gaming ITX-ac model crashed instantly every time the small FFT torture test within Prime95 was initiated. At anything on the CPU VCore above 1.35 V would result in instant instability. The Ryzen Master auto-overclocking function failed every time it tried to dial in settings, but it does, however, operate absolutely fine at stock, and with Precision Boost Overdrive enabled.  Either the firmware is the issue, or the board just isn't capable of overclocking the Ryzen 3700X with extreme workloads with what is considered a stable overclock on the X570 chipset. We will re-test this in the future.

Comparing the ASUS Pro WS X570-Ace to other models on test with our Ryzen 7 3700X processor, we found that at the time of writing, this particular model has the most efficient power delivery design so far. The teaming of the power stages from a 12+2 to a 6+1 design works well and as a result, runs around 7°C cooler than the MSI MEG X570 Godlike at maximum load. One drawback to the ASUS Pro WS X570-Ace is that this model doesn't include a VRM temperature sensor integrated into the power delivery, but our thermal probe readings and thermal imaging are consistent, and the WS X570-Ace performs superbly in comparison to both the MSI MEG X570 models we have tested so far.

Ryzen 3000 Overclocking ASUS Pro WS X570-Ace Conclusion
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  • CrystalCowboy - Monday, August 12, 2019 - link

    Look up the specs on the Micron 9300. That should give you appreciation of what is going on in U.2.
  • TheUnhandledException - Monday, August 12, 2019 - link

    Yeah it would have been nice to even have it be m.2 OR u.2 can only use one or the other. Having a half speed m.2 on a workstation board seems a bad design tradeoff. I mean I guess you could use one of those x8 expansion slots for two more m.2 but the onboard m.2 should be full speed in this segment.
  • CheapSushi - Tuesday, August 13, 2019 - link

    U.2 port is the 2nd most versatile port other than PCIe. Too many "enthusiasts" don't seem to understand it. In fact, you can connect M.2 drives to it, at x4 also. You can even use a cable to hook up 4 SATA drives to it. You can connect an actual U.2 drive too. There's so many options with it.
  • TheUnhandledException - Tuesday, August 13, 2019 - link

    You can not connect SATA drives to a u.2 port. You can connect a NVMe m.2 drive to a u.2 port with an adapter but you can also connect a u.2 drive to a m.2 port with an adapter. Given the relatively pricing of u.2 vs m.2 drives short of needing a storage server with 20+ NVMe drives there is little reason to prefer a u.2 port over an m.2 one.
  • Hul8 - Monday, August 12, 2019 - link

    Writer: Please check the meaning of "phase".

    This is not by any means a 12 phase design. It only has 6 distinct phases on main components. Teaming only increases the capacity (per phase).
  • 3DoubleD - Monday, August 12, 2019 - link

    Agreed, this bothered me too. If it is a 6+2 controller and there is no doubler, the CPU only receives 6 distinct phases, regardless of the extra chips on the other end. Mobo manufacturers make this complicated enough to sort out, I'd hope these reviews would be more accurate and transparent than the motherboard's marketing page.

    Whether this makes a significant difference for the intended use case is another thing. They hit the same OC on your Ryzen 3700x sample that you did with the top end x570 boards, so it seems plenty capable with 6 phases to meet the power delivery needs for this CPU, even OC'd.
  • bananaforscale - Monday, August 12, 2019 - link

    This. Go watch Buildzoid videos.
  • Jaguar36 - Monday, August 12, 2019 - link

    Does the RTL8125G included with some of Asus's other X570 boards also have a similar POST time hit?
  • TheUnhandledException - Monday, August 12, 2019 - link

    Nearly perfect but only 2 lanes on the second m.2. Yuck.
  • eva02langley - Monday, August 12, 2019 - link

    The price of these motherboards are getting ridiculous. They cost more than the CPUs.

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