Ryzen 3000 RDRAND microcode bug
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=12770
Printed Date: 03 Aug 2025 at 12:47pm
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: Ryzen 3000 RDRAND microcode bug
Posted By: ncc1701z
Subject: Ryzen 3000 RDRAND microcode bug
Date Posted: 30 Oct 2019 at 5:28am
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Just now I read about a microcode bug here: https://arstechnica.com/gadgets/2019/10/how-a-months-old-amd-microcode-bug-destroyed-my-weekend/ As it turns out, Ryzen 3000 series shipped with a broken random number generator. It gives you a 0xFFFFFFFF for the "random" number, every single time. For some systems (especially Linux) it made them unable to boot. Destiny 2 on Windows also can't run because of it. Apparently it should've been fixed with a BIOS update, but it seems not to be the case even today. Article explained how to check if your system is affected, but it required Linux. For anyone willing to do the check and share their results, I am grateful. I hope ASRock had this problem fixed. |
Replies:
Posted By: Ray62
Date Posted: 30 Oct 2019 at 6:03am
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These problems are fixed since over two months. Since "AMD AGESA Combo-AM4 1.0.0.3 ABB" the RDRAND problem is fixed (for Linux systemd and Destiny 2 on Windows, but also for all SW using the RDRAND instruction). So a bios must contain at least this AGESA version, which should be the case for all consumer/mainstream boards from Asrock supporting Zen2 CPUs. ------------- Asrock Fatal1ty X370 Professional Gaming Offline Under test: MSI X570_MEG_ACE | AMD Ryzen 9 3900X | Scythe Mugen5 | 2x16GB F4-3200C14D-32GTZ@3466 | ASUS GeForce GTX 1080 Ti FE |
Posted By: ncc1701z
Date Posted: 31 Oct 2019 at 3:25am
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You would be right, that should've been the case. Except the mainboard in the article didn't get the fix even now. Granted, it's a rather niche board (Asrock Rack X470D4U), but that situation shouldn't happen. Oh well, maybe it's just a special case and I'm just being paranoid 
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Posted By: shmerl
Date Posted: 31 Oct 2019 at 11:23am
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On Linux you can also explicitly load latest microcode, even if motherboard firmware still ships the old one: https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/amd-ucode |