AMD Motherboards - X750 Pro4 - no video with CSM disabled

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X750 Pro4 - no video with CSM disabled

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=17472
Printed Date: 13 Aug 2025 at 3:12pm
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: X750 Pro4 - no video with CSM disabled

Posted By: r1348
Subject: X750 Pro4 - no video with CSM disabled
Date Posted: 11 Dec 2020 at 1:49am

Hello,

I wanted to disable CSM from my BIOS settings to be able to enable "Above 4GB decoding" for video memory, which is basically SAM, but if I disable CSM I completely lose video output until the OS takes over. This also means that I can't see the BIOS configuration anymore and have to use the CMOS jumper to reset the mobo to factory settings.
My previous motherboard, an ASRock H77 Pro4/MVP, was working fine with CSM disabled with the same graphics card.

Here's my system specs:

AMD Ryzen 7 3700X
ASRock X570 Pro4
Sapphire Nitro+ RX580 SE
2x8GB Crucial DDR4-3600
2x512GB Samsung 850 Pro

Anyone known if there's any known bad UEFI interaction between my mobo and my graphics card?

Thanks!

Replies:

Posted By: r1348
Date Posted: 11 Dec 2020 at 1:56am

It looks like someone else is having the same issue with AMD ASRock mobos and Sapphire video cards:

https://www.reddit.com/r/ASRock/comments/jes2x0/disable_csm/
https://www.reddit.com/r/ASRock/comments/gc4936/b450_itx_fatal1ity_bios_not_showing_up_after/