You may be aware of the newly-exposed, 20 year old vulnerabilities in Intel (and possibly other) CPUs, know as Meltdown or Spectre. Below is information specific to this exploit as released by Microsoft and Green Cloud.
Microsoft:
Microsoft released a security update on 1/3/2018 to address the critical vulnerabilities in virtually all modern CPUs. This patch requires a registry key setting by made by antivirus software before the security update will install. This registry key is for the antivirus software to acknowledge it is compatible with the security update. This Microsoft patch is intended for all currently support operating systems.
See the Microsoft advisory regarding the registry key setting at the following link:
https://support.microsoft.com/en-us/help/4072699/january-3-2018-windows-security-updates-and-antivirus-software
You can also review a list antivirus vendors and their status and any caveats related to the registry key at the following link:
https://docs.google.com/spreadsheets/d/184wcDt9I9TUNFFbsAVLpzAtckQxYiuirADzf3cL42FQ/htmlview
Green Cloud Hosted Servers:
For clients running virtual servers hosted by Green Cloud, they will begin patching firmware and hypervisor software in their data centers no later than 1/15/18. Green Cloud will be patching one data center at a time beginning in Phoenix, AZ. In testing the hypervisor patches, performance hits of 5-10% were seen. Intel’s firmware and microcode updates appear to solve much of the performance problems, although there have been some reports of stability problems with the CPU. Green Cloud is working to balance the timing of their patches with the best information available from Intel.