Printed From: ASRock.com
Category: Technical Support
Forum Name: AMD Motherboards
Forum Description: Question about ASRock AMD motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=8081 Printed Date: 11 Feb 2025 at 12:01am Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: Above 4GB MMIO Enable not working on AM4 boards?Posted By: pbfarmer
Subject: Above 4GB MMIO Enable not working on AM4 boards?
Date Posted: 16 Mar 2018 at 7:47am
" rel="nofollow - Has anyone gotten the "Above 4GB MMIO" feature to actually work on an AM4 board (i.e. verified addressing assignments above 4GB)?
I have a Fatal1ty X370 Gaming K4 board, and the latest UEFI finally includes an option which should allow assigning address space above 32bits called 'Above 4GB MMIO Enable'. However, toggling this feature on doesn't seem to actually do anything - with 7 GPUs installed, each using >260MB of addressing space (or >1.8GB total) all device addressing remains in the 32 bit space (under 4GB.)
Adding an 8th card causes the machine to fail to POST with a '0d' error. My hunch is that this is due to running out of address space, so I'd like to force assigments above 4GB, but can't figure out how to get this feature to work.