The ASUS Pro WS X570-Ace Review: x8x8x8 with No RGBby Gavin Bonshor on August 12, 2019 9:00 AM EST
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.
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
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
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.
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.