z370m pro4 VRM phases
Printed From: ASRock.com
Category: Technical Support
Forum Name: Intel Motherboards
Forum Description: Question about ASRock Intel Motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=6376
Printed Date: 08 Aug 2025 at 11:46am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: z370m pro4 VRM phases
Posted By: xpl
Subject: z370m pro4 VRM phases
Date Posted: 20 Oct 2017 at 5:19pm
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Aloha, The VRM implementation on this board is provided by the http://www.intersil.com/en/products/power-management/computing-power-vrm-imvp/multiphase-controllers/ISL95856.html" rel="nofollow - ISL95856 "4+3 Multiphase PWM Regulator" The marketing statement on the http://www.asrock.com/mb/Intel/Z370M%20Pro4/index.us.asp" rel="nofollow - ASRock page for the z370m pro4 states "10 Power Phase design" How, might you wonder, does a 4+3 controller produce 10 distinct phases? I wondered, and pulled out my DMM on continuity mode. In reality, what appear to be 11 chokes around the z370m pro4 socket, are 6 chokes. Ten of the chokes are configured in parallel pairs of two chokes, making a total of five phases plus the one remaining which I assume is for VTT. What is more awkward is that the totem-pole mosfets are configured in quads. Paralleled lower-quality SM4336N mosfets act as the upper mosfet of the totem, and two paralleled higher-quality SM4337N mosfets act as the lower mosfet of the totem. ASRock, please explain the marketing. I was convinced that this would be 10 distinct power phases. I am not comfortable overclocking on something which is - in reality - 3+2, or 3 phases for the processor, 2 for the iGP.  |
Replies:
Posted By: xpl
Date Posted: 20 Oct 2017 at 6:13pm
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" rel="nofollow - Furthermore, why are those top mosfets not heatsinked? This is especially concerning because the motherboard has been designed to accommodate a heatsink for those fets as there are through-hole mounting points there labeled "MOS_HEATSINK2" |
Posted By: Milan
Date Posted: 16 Dec 2017 at 3:13am
| " rel="nofollow - Any answer ? I'm curious too.... |
Posted By: Maxmiz
Date Posted: 16 Dec 2017 at 8:19pm
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I understand why there's so much vdrop. Plus the top ones don't heat up, it looks like they're not even activated. |
Posted By: mark5916
Date Posted: 24 Jul 2018 at 9:39pm
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I registered only to answer the question of The OP. As you know that this board uses an Intersil ISL95856 PWM controller... That PWM controller can do a 4-, 3-, 2-, or 1-phase design for the CPU VCC, and a 3-, 2-, or 1-phase design for the VCCGT (integrated graphics processor) ON that board (as with many other budget boards) ASRock uses a 4+3 phase design. ASRock doubles the number of power stage components on the CPU VCore rails to get eight phases. But in reality that's a 4 phase (with double the mosfets [most probably] in parallel mode) So, two low side and two high side mosfets (removing the mosfets heat sink would help on that matter) and double the inductors. The remaining three phases are for the IGP. So, as you very well have formulated, that's a 4+3 phase design board! :)
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