You are probably familiar with the terms firmware and drivers in the context of computer hardware, and the endless updating that they require. Most people associate these drivers and firmware updates with peripheral equipment such as graphic cards and DVD drives. You might not however be aware that you can also update the firmware on your CPU (firmware is called microcode in CPU speak).
These microcode updates are normally bundled in with BIOS updates. Given the fact that BIOS updates are inherently risky, motherboard manufacturers are reluctant to issue BIOS updates for anything other than major bugs. This means your microcode can become quite dated. Both Intel and AMD realise this and release standalone microcode updates.
If you are running Debian or Ubuntu and Intel CPU (there is a pretty good chance you are), you can use the intel-microcode and microcode.ctl packages to update your microcode. This will download the latest microcode for your CPU and apply the update automatically on each boot. This process does not apply the update permanently, and is completely reversible.
to download the latest microcode version from Intel.
I'm not aware of any analogous utility for Windows, but if anyone does, let me know in the comments.