The ASRock Z590 OC Formula Review: An Iconic Brand Revival

Power Delivery Thermal Analysis

Recently, a lot more focus has been put on power delivery specifications and capabilities, not just by manufacturers, but as a result of users' demands. In addition to the extra power benefits from things like overclocking, more efficient designs in power deliveries and cooling solutions aim to bring temperatures down. Although this isn't something most users ever need to worry about, certain enthusiasts are bringing more focus onto each board's power delivery. The more premium models tend to include bigger and higher-grade power deliveries, with bigger and more intricate heatsink designs, with some even providing water blocks, while others are spending more just to make sure the most efficient parts on the market are being used.

The 16-phase power delivery on the ASRock Z590 OC Formula (operating in 8+0 with doublers)

Testing Methodology

Our method of testing is if the power delivery and its heatsink are effective at dissipating heat. We do this by running an intensely heavy CPU workload for a prolonged method of time. We apply an overclock, which is deemed safe and at the maximum that the silicon on our testbed 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 before testing, I binned 10 and selected the most accurate (within 1c of the actual temperature) for better parity in our testing.

To recreate a real-world testing scenario, the system is built into a conventional desktop chassis which is widely available. This is to show and alleviate issues when testing on open testbeds, which we have done previously, which allows natural airflow to flow over the power delivery heatsinks. It provides a better comparison for the end-user and allows us to mitigate issues where heatsinks have been designed with airflow in mind and those that have not. The idea of a heatsink is to allow effective dissipation of heat and not act as an insulator, with much more focus from consumers over the last couple of years on power delivery componentry and performance than in previous years.

For thermal imaging, we use a Flir One camera to indicate 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 73.6ºC on the hottest part of the CPU socket during our testing

The ASRock Z590 OC Formula is using a 16-phase power delivery specifically for the CPU, with no SoC section. For the CPU, there's a total of sixteen Intersil ISL99390A 90 A power stages which are operating in a parallel design with eight Intersil ISL6617A doublers. Regulating the power delivery is an Intersil ISL69269 PWM controller operating in an 8+0 mode. Keeping the power delivery cool is a two-section heatsink that is interconnected by a single heat pipe, and combines a large metal rear panel cover which adds some extra surface area to the design. Assisting in the cooling of the power delivery is a pair of small cooling fans which are installed onto the smaller of the two heatsinks, and when forced to full speed were audible when placed in our regular test chassis.

Looking at our VRM thermal testing results, the ASRock Z590 OC Formula performs very well in our testing and as expected due to the active cooling solution, performs better than most of the boards we have tested. Using our FLIR thermal imaging camera, we saw temperatures of 73.6°C on the hottest part around the CPU socket area which is slightly warmer than the power delivery area. In terms of data, the integrated thermal VRM sensor maxed out at 65°C, while the readings from our pair of K-type thermocouples were 69 and 68°C respectively. 

Overall the ASRock Z590 OC Formula fared well in our power delivery thermal testing, and with the active cooling solution working well, it's one of the better designs we've seen so far on Z590.