AMD Motherboards - x399 taichi no boot with bifurication on, 4x4x4x4

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x399 taichi no boot with bifurication on, 4x4x4x4

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=19501
Printed Date: 08 Aug 2025 at 7:00am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: x399 taichi no boot with bifurication on, 4x4x4x4

Posted By: smoothrun
Subject: x399 taichi no boot with bifurication on, 4x4x4x4
Date Posted: 01 Sep 2021 at 6:12pm

MB: x399 taichi bios 3.90 and 3.50 tested.
cpu tr 1950x

So i have a pcie splitter card connected to 4 U.2 nvme disks. both confirmed working on another amd system with bifurication 4x4x4x4 on.
but on my x399 taichi i connect it to the pcie 4 slot(set to 4x4x4x4 mode), and as soon as i have more than 1 nvme connected to the slot it halts at boot code 94.
if i disconnect all but one of the nvme drives it boots fine.
so far ive tested turning iommu on/off.
pcie1 has a 16x gpu
pcie2 has a 4x card working fine
pcie4 has the pcie16x to 4x u.2 plugs only works with 1 nvme connected.
pcie5 has a 4x card working fine.

Replies:

Posted By: smoothrun
Date Posted: 01 Sep 2021 at 6:13pm

it stops at post code 94 fwiw