Sandy Bridge and Ivy Bridge Linux Overclocking Guide
Overclocking has historically been the best friend of those concerned with complete control of their system and maximum performance, two things Linux is well known for, so it only makes sense that the two would go hand in hand. Though overclocking has become increasingly less difficult, it still remains in the foggy distance beyond the perimeter of the average user's experience. There is no reason why it needs to remain there. With the plethora of tools to monitor a system's “vitals” and modern processors, especially those with unlocked multipliers, overclocking is well within the reach of even the moderately experienced user. This particular guide focuses on the Intel Sandy Bridge and Ivy Bridge chips, though many of the steps discussed can easily apply to most AMD chips, and assumes that you have a chip with an unlocked multiplier. For the Sandy and Ivy chips, these are the ones that end in a “k.” Before touching the BIOS and changing any multipliers, the system needs to be set up and prepared to test the overclock for stability. The main tools needed are; a stress testing software, a CPU frequency monitor, and a CPU temperature monitor. There are many options out there, but this guide will use Mprime for stressing, i7z for frequency monitoring, and gkrellm for temperature. Mprime is probably the easiest to set up. Simply go to http://www.mersenne.org/freesoft/ and download the appropriate version and untar. I7z is going to require some compilation, but is totally worth it. If you are running Arch or Gentoo, it's already in your repository, so you can just download it that way. If not, to download it, go to http://code.google.com/p/i7z/downloads/list and download the latest version and untar. Open up a terminal and type: cd /where/you/unpacked/i7z make su make install The final part of the setup is to install gkrellm. Gkrellm is an excellent all purpose monitoring program, however; i7z still tends to work better than any of the CPU monitoring plugins for gkrellm. Gkrellm uses lm_sensors to detect the CPU's temperature. To install and configure lm_sensors: su apt-get install lm_sensors yum install lm_sensors pacman -S lm_sensors emerge lm_sensors (choose whichever one suits your distro) sensors-detect Answer “yes” to each question. When it's done, restart your system. When the system reboots, open up a terminal and install gkrellm. It's in just about every distro's repository, so you shouldn't have trouble finding it. After it's installed, open it up and press F1 to open the configuration. From there navigate to builtins, then sensors, temperature, and check the boxes for your CPU's cores. That's it. Now to overclock. Restart your system, and boot into the BIOS(UEFI if you have a newer board). The way to enter each board's BIOS is different. On most boards, it's pressing “delete” immediately following the POST. From here, the goal is to raise the multiplier, gradually stepping it up and testing. Do not change the base clock. It is not needed and will complicate things. As you step up the multiplier, you may also want to step up the Vcore or core voltage. The terms are interchangeable based on your board. Keep in mind that the max “healthy” Vcore for Sandy and Ivy is 1.4v, but 1.375v is about the top you'd ever want to run it at regularly. It should be noted that there are other settings on the motherboard that may hinder overclocking. Be sure to consult your board's manual for specifics. Save your settings and reboot. If your system boots normally, then you're ready to test. If not, restart into the BIOS again and step back your multiplier and Vcore. Open gkrellm. Then open a terminal, su, and run i7z. Now cd to the directory where you unpacked Mprime and run ./mprime. Observe carefully to make sure that the CPU frequency is what you set it at in i7z, and that the temperature in gkrellm doesn't climb above 75 degrees Celsius. 75 degrees Celsius is the absolute max for Sandy and Ivy chips. If you want to run a stable overclock constantly, 65-70 degrees would be an ideal maximum. Let the system run that way for at least two to three hours. If everything remains running and the temperature remains within the “healthy” range, you have a stable overclock. If it freezes, goes above 75 degrees, or malfunctions in any way, go back step back the voltage and/or the multiplier and test again until you have a stable overclock. Congratulations! You've successfully overclocked your computer in Linux!