https://forum.asrock.com/ Copyright (c) 2006-2013 Web Wiz Forums - All Rights Reserved. Tue, 23 Jun 2026 13:32:20 +0000 Sun, 09 Dec 2018 02:47:54 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.04 360 https://forum.asrock.com/RSS_post_feed.asp?TID=10357 https://forum.asrock.com/forum_images/web_wiz_forums_black.png https://forum.asrock.com/ https://forum.asrock.com/forum_posts.asp?TID=10357&PID=58619&title=csm-disabled-vs-csm-all-uefi-only#58619 Author: keeka
Subject: 10357
Posted: 09 Dec 2018 at 2:47am

How does the behaviour of the motherboard differ between these two setups:

1. CSM disabled

2. CSM enabled plus Storage/Video/NIC each set to launch UEFI oprom only.

I was inclined to think these two configs would do the same.
However, they do not. I find I need to turn on CSM and enable UEFI video OPROM in order for windows 7 login and desktop to appear on dedicated graphics (with iGPU disabled). With CSM disabled, the screen does not get past windows boot logo, though the system is otherwise functional.
Also, with storage OPROM set to UEFI only, the F11 boot menu displays non UEFI boot disks as well as meaningless (to me) characters.
Doesn't make sense at all to me.
Motherboard: Asrock H170M Pro4
bios 7.2
CPU i5-6600
dGPU AMD RX 580

Hopefully someone can explain the difference between csm off vs csm on and all suboptions set to UEFI OPROM only.

Thanks.]]> Sun, 09 Dec 2018 02:47:54 +0000 https://forum.asrock.com/forum_posts.asp?TID=10357&PID=58619&title=csm-disabled-vs-csm-all-uefi-only#58619