VRM Overview

Specifications

The ASUS ROG Crosshair VIII Impact features a 6 phase VRM in a 4 + 2 configuration. No doublers are used; instead, two power stages are used in parallel for each phase to double the current-carrying capacity.


This ASP1405 controller supports the maximum of eight phases. ASUS ditched doublers under the assertion that a blind-parallel VRM design significantly improves transient response times as it does not have to divide the PWM signal from the controller in half for each phase. Real-world results in my testing show generally equivalent performance. There is so much more that goes into VRM design—it is very hard to compare two different implementations. This is at the very least a cost saving for ASUS as high-quality doublers are not cheap.


The ASUS ROG Crosshair VIII Impact uses the Infineon TDA21472 across the board. These top-of-the-line 70 A power stages give ASUS a total of 140 A per Vcore phase. The eight Vcore power stages are all lined up just to the left of the socket, while the two SOC power stages are on the back of the board, above the socket backplate.

With a maximum theoretical Vcore output of 560 A, the ASUS ROG Crosshair VIII Impact has more than enough for even the top spec AMD Ryzen 3950X under LN2.