Earlier today we already posted news that some AMD platforms have issues with the new Microsoft Spectre and Meltdown patches. Some end-users ended up into systems not booting after Microsoft applied the patch.
AMD just send out a small statement on that, I'll just post that as -is:
-- AMD --
AMD is aware of an issue with some older generation processors following installation of a Microsoft security update that was published over the weekend. AMD and Microsoft have been working on an update to resolve the issue and expect it to begin rolling out again for these impacted shortly. Also, we wanted to make it clear this patch is to address GPZ Variant 1 (one of the variants of Spectre) and not GPZ Variant 3 (Meltdown).