Attempts to mitigate CPU flaws affecting practically every processor released in the past two decades has not been easy. There is no 'one-size-fits-all' solution to this mess, and some of early attempts to patch CPUs against Spectre and Meltdown only caused more problems, like random reboots. Well, good news if you an own an older processor—Intel has released another batch of stable microcode updates, this time for Haswell and Broadwell CPUs.
The new microcode updates replace some of the ones Intel briefly doled out in January. Intel ended up pulling those initial patches after customers complained of random reboot issues. To Intel's credit, the company responded quickly and identified the root cause, then told its hardware partners to stop dishing out the updates to its customers.
"We recommend that OEMs, cloud service providers, system manufacturers, software vendors and end users stop deployment of current versions, as they may introduce higher than expected reboots and other unpredictable system behavior," Navin Shenoy, Executive VP and GM for Intel's Data Center Group, said at the time.
Intel updated its Microcode Revision Guidance (PDF) to reflect the updated microcode. Almost every Broadwell and Haswell entry shows that updated firmware has reached "Production" status, which indicates that Intel has completed all the necessary validation steps and is now authorizing its partners and customers to apply the new firmware. The only Broadwell and Haswell parts that have not yet reached Production status are Intel's Xeon E7 v4 (Broadwell) and Xeon E7 v3 (Haswell) product families. However, Intel and its partners are currently testing beta firmware on both, the last step before going into Production status.
It seems Intel is prioritizing its efforts on newer generation processors, as stable microcode updates already exist for most Coffee Lake, Kaby Lake, and Skylake processors. Updates for Ivy Bridge and Sandy Bridge are in beta testing at the moment, while several others are in the pre-beta or planning stage, such as Nehalem, Wolfdale, Yorkfield, and so forth.
Doling out updates is only part of the process. Microsoft in January said that Windows 10 PCs running Haswell or older Intel CPUs would see significant slowdowns after applying the necessary patches, including firmware updates and software fixes. Now that stable firmware has arrived, Microsoft and others can tweak and optimize their own patches to minimize any potential performance hits.