Boy have been asking a bunch of questions on here lately, I have always been curious about this other driver called the CPU Microcode driver, I have an intel i3 Core Processor. I understand that this will increase your CPU performance with Ubuntu pretty well, but I'm not sure if I should install it.
Best Answer
Installing a microcode update is generally a good idea, as it can fix known problems or vulnerabilities in your CPU. While these can be patched with a BIOS/UEFI update, doing so in Ubuntu as well adds additional assurance that the patch is effective and can help you make sure it is patched sooner.
The microcode in a CPU is basically a translation layer between machine code from your software and the inner workings of the CPU. It teaches the CPU what to do in response to machine code instructions. An update may be installed in your BIOS/UEFI interface, and it can also be loaded by your operating system at boot. In addition to fixing bugs or vulnerabilities, an update may sometimes negatively or positively affect performance, though not often in a significant way.
Note: I updated this answer because it was originally written in 2016 before CPU security flaws such as Meltdown and Spectre were known and before I started thinking of microcode updates as important for security.