Editing BIOS (section)

=== Processor microcode updates ===
[[Intel]] processors have reprogrammable [[microcode]] since the [[P6 (microarchitecture)|P6]] microarchitecture.<ref name="Stiller_1996"/><ref name="Mueller-1"/><ref name="microcode-09"/> [[AMD]] processors have reprogrammable microcode since the [[K7 (microarchitecture)|K7]] microarchitecture. The BIOS contain patches to the processor microcode that fix errors in the initial processor microcode; microcode is loaded into processor's [[Static RAM|SRAM]] so reprogramming is not persistent, thus loading of microcode updates is performed each time the system is powered up. Without reprogrammable microcode, an expensive processor swap would be required;<ref name="Mueller-2"/> for example, the [[Pentium FDIV bug]] became an expensive fiasco for Intel as it required a [[product recall]] because the original Pentium processor's defective microcode could not be reprogrammed. Operating systems can update [[main processor]] microcode also.<ref>{{Cite web|title=KB4100347: Intel microcode updates|url=https://support.microsoft.com/en-us/help/4100347/intel-microcode-updates-for-windows-10-version-1803-and-windows-server|access-date=2020-09-20|website=support.microsoft.com}}</ref><ref>{{Cite web|title=Microcode - Debian Wiki|url=https://wiki.debian.org/Microcode|access-date=2020-09-19|website=wiki.debian.org}}</ref>