According to Intel's Microcode Revision Guidance paper, they have released new microcode updates for Sandy Bridge and Ivy Bridge to deal with the Spectre and Meltdown vulnerabilities. Next up are Westmere Xeons, Nehalem Xeons, as well as some Arrandale and Clarkdale CPUs, with Arrandale, Bloomfield, Clarkdale, and Clarksfield still in the pre-beta stage. While Intel may be releasing the microcode updates, it is still up to the manufacturers to provide a BIOS update in order to get the new microcode. As of the time of writing, I'm still waiting for the update from MSI for my X99 board that was released last month. We have compiled a list of motherboard manufacturer sites here, but make sure to look up your specific board to be sure if it has been updated or not.