Lesson 03 – BIOS Settings and Overclocking to 3.2GHz

BIOS Information Screen

I’ve just powered on the computer and before we enter the BIOS I need to point something out.  This is what is generally called a BIOS information screen.  The information goes by very quickly so I’ve pressed the Pause-Break key to pause it.  Pressing any other key will un-pause it.  It shows the CPU model, its actual speed in MHz, the speed of the memory and lots of other information that is useful when overclocking.  Most motherboard makers cover this information screen up with a logo screen.  There is a key to press, typically Tab, to hide the logo screen and show this information screen, but you have to hit Tab every time you want to look and a lot of the time the information you need is gone before the Tab command takes effect.  The first thing we’re going to do in the BIOS is make sure that the logo screen is turned off.  I’ll press any key to continue and on this computer I need to press F2 to enter the BIOS setup.  On some computers it’s the Delete key to enter the BIOS setup.

BIOS Layout

This is the BIOS main menu. It has several menu choices at the top that take you to different sections of the BIOS.  Here’s another common main menu layout with its sections laid out on one common page.  Just about every motherboard maker uses one of these two layouts.  These videos are concentrating on overclocking so we’re not going to get into most of these options.  The Home PC Builder videos have a video that covers the BIOS in general and it’s Lesson 1 of the Computer Setup Lessons.

The logo screen setting in this BIOS is under Boot and Boot Settings Configuration.  It’s called Full Screen Logo and it is Disabled so it won’t come up.  On other BIOSs it can be found under Advanced BIOS Features, called Full Screen Logo Show.  The default is Enabled.  You can select it and disable it.

I’ll hit Esc a few times to get back to the Main Menu.  In this BIOS the majority of settings that have to do with overclocking are in the AI Tweaker section.  Most BIOSs have a section like this.  Gigabyte calls theirs MB Intelligent Tweaker or M.I.T. You can find EVGA’s version under Frequency/Voltage Control and MSI calls theirs Cell.  If your motherboard doesn’t have a section like this or you can’t find the options you see here in your BIOS then you won’t be able to overclock the CPU.  This is fairly rare these days, but just to be on the safe side, before you buy a motherboard go to the maker’s website, download the motherboard manual and look for these settings.

Disabling Power Saving Features and Turbo Mode

Next, we’re going to find and disable the CPU’s Turbo mode and power saving features so we have control over the speed of the CPU.  In this BIOS the Turbo and Speedstep settings are in the AI Tweaker, but most are in a different section.  We’ll go there to disable them all.   They are in Advanced and CPU Configuration.  The power saving features include Turbo mode, C1E Support, C-State Tech and SpeedStep. These are dependent on each other so if you disable one a few others may disappear as well. It’s the same as disabling them.  On a Gigabyte motherboard these settings are in the MIT and Advanced CPU Core Features. You need to disable Turbo mode, CPU Enhanced Halt, C State Support and CPU EIST Function.  On a EVGA motherboard these settings are in the Frequency Voltage Control and CPU Feature.  You need to disable Speedstep, Turbo mode and CxE Function. On an MSI motherboard the settings are in the Cell menu, CPU Specifications and CPU Technology.  You need to disable Intel Turbo Boost tech, Intel EIST and Intel C-State tech.

Frequency and Multiplier Settings

I’ll hit Esc and switch to the AI Tweaker and Speedstep shows as disabled, turbo mode has disappeared meaning it is disabled. So let’s move on to the overclocking related settings. Here we have the CPU Ratio Setting.  This is the multiplier which the stock setting on our CPU is 20.  In this BIOS I have to key in the setting directly which I will go ahead and do.  I don’t see the base clock here.  In order for it to show up as an option to change I have to change the AI Overclock Tuner setting from Auto to Manual.  I can do this by pressing enter and selecting it or by press the minus key to scroll through the options. The Base clock is at its default of 133Mhz. If we multiply the base clock by the CPU ratio 133 x 20 we get 2660 or 2.66GHz which is the current speed of the CPU. To overclock the CPU we will increase the MHz of the base clock, but I will leave it at its stock setting for now.

We don’t need to worry about the PCIE Frequency and can leave it alone.  Below that we see the three other frequencies that will be effected then we change the base clock. The Memory frequency setting which controls the speed the actual memory sticks run at is called the DRAM Frequency and is set to Auto.  I can change that to the speed of the memory we have installed in this computer, which is 1333MHz, but again I’m going to leave it alone for now.  The uncore frequency, which controls the speed of the memory controller and cache built into the CPU, is set to Auto.  I can press enter to change it.  The QPI Link Data Rate, which controls the speed of the interface between the CPU and the rest of the motherboard, can be changed the same way.  Your motherboard’s BIOS may be showing the multiplier used to determine each of the settings. For instance, a memory speed of 1333MHz is the result of multiplying the base clock which is 133MHz times 10.  So the multiplier used to get the 1333MHz speed is 10.  The Uncore and QPI speeds are a result of the base clock time a multiplier as well.  On our BIOS here only the resulting speeds are shown.  After we increase the base clock to speed up the CPU we will use these three settings to under-clock the memory, uncore and QPI to keep the system stable.

To find these frequency and multiplier settings on a Gigabyte motherboard go to the MIT and Advanced Frequency Settings. The CPU multiplier setting is called CPU Clock Ratio here. The Base clock is called Base Frequency and to access it you need to Enable Base Clock Control.  The memory multiplier is called the System Memory Multiplier.  The Uncore frequency can be changed using the Uncore Clock Ratio and the QPI Link Data Rate can be changed using the QPI Clock Ratio.

On an EVGA motherboard you can find these settings in the Frequency/Voltage Control section. The CPU multiplier setting is called the CPU Clock Ratio.  The base clock is called the CPU Host Frequency.  The CPU Uncore Frequency setting is here.  You can find the Memory frequency setting in Memory Feature and it’s called the Memory Frequency.  The QPI setting is in CPU Feature. To change its setting you need to Enable the QPI Controller Setting.  You then have access to change the QPI Frequency Selection.

On a MSI motherboard you can find the frequency and multiplier settings in the Cell menu.  The CPU multiplier setting is called Adjust CPU Ratio.  The base clock setting is here.  The memory frequency setting is called the Memory Ratio here.  The uncore frequency setting is called the uncore ratio and the QPI setting is called the CPU ratio.

We will come back to the frequencies and multipliers in a moment.

Voltage Settings

Next, we need to identify the voltage settings.

Back on our motherboard the voltage settings are lower on the AI Tweaker.  The CPU Voltage controls the voltage going to the individual CPU cores.  The CPU PLL Voltage controls the voltage going to the Phase Locked Loop which is a control system for the CPU.  The QPI/DRAM Core Voltage controls the voltage going to the cache and memory controller on the CPU.  Finally, the DRAM Bus Voltage controls the voltage going to the memory sticks themselves.

On a Gigabyte motherboard the voltage settings can be found in the MIT and Advanced Voltage Settings.  The CPU Voltage is called CPU Vcore.  The CPU PLL Voltage is called CPU PLL.  The QPI/DRAM voltage is called QPI/Vtt Voltage and the DRAM Bus Voltage is called DRAM Voltage.

On a EVGA motherboard the voltage setting can be found in the Frequency Voltage Control Menu and Voltage Control.  The CPU Voltage is called CPU Vcore.  The CPU PLL Voltage is called CPU PLL Vcore.  The QPI/DRAM voltage is called QPI PLL Vcore and the DRAM Bus Voltage is called DRAM Voltage.

On a MSI motherboard the voltage settings can be found in the Cell menu.  The CPU Voltage is here.  The CPU PLL Voltage is called CPU Vcore.  The QPI/DRAM voltage is called QPI Voltage and the DRAM Bus Voltage is called DRAM Voltage.

That is all the settings we will be using to overclock.  For our first attempt we are going to leave all of the voltages at their stock settings and see how far we can push the CPU using only the frequency and multiplier settings.

To make sure the voltages stay at their stock settings we are going to directly key them in.  If we leave them set to Auto, there is a strong possibility the motherboard will automatically increase them when we start manually increasing the frequencies.  The default voltages are 1.2 for the CPU Voltage, 1.8 for the CPU PLL voltage, 1.2 for the QPI/DRAM voltage and 1.5 for the memory voltage.  You need to check your RAM to be sure, some RAM for Core i5 and i7 systems take up to 1.65 volts.  The RAM we have installed does take 1.5V.

Overclocking to 3.2GHz

For our first overclock we are going to attempt to get the CPU up to 3.2GHz.  This is a very moderate overclock and shouldn’t be any problem.  To reach 3.2GHz we need to set the base clock to 160MHz.  160 x the multiplier which in our case is 20 gives us 3200 or 3.2GHz.  Your BIOS may automatically compute and show the resulting CPU speed.  We don’t need to change the PCIE Frequency because it is not linked to the base clock.

I’ll skip down to the DRAM Frequency and press enter.  Here we are given several speed options to choose from. Our RAM is rated to run at 1333MHz. We have two settings, one slower and one faster, to choose from.  If I were to choose 1604MHz the memory would be overclocked far above what it is rated for and would probably cause system instability just on its own regardless of how the CPU is overclocked. One of the most important rules about overclocking is that you DON’T want to try overclocking more than one component at a time.

If we choose the 1604MHz option, restart and go run Prime95 to stress test the system, the RAM would almost certainly make the test fail or cause the system to restart while Prime95 is running . At that point we really would not know if the CPU was stable at the 3.2GHz speed or not. So we will choose the 1282MHz option. This will be under-clocking the RAM, and yes this will make the RAM slower, but the resulting performance improvement from the CPU overclock will more than make up for it.

Next is the uncore frequency.  There is a rule here you MUST follow and on the right our BIOS is telling us that we must choose an uncore frequency at least double the speed of the RAM.  I’ll press Enter and the top option is just over twice the speed of the RAM so I will choose it.

Last is the QPI link rate.  I’ll press enter on it and choose the lowest option.  You want to always choose the lowest option  for the QPI when overclocking. The QPI speed doesn’t effect performance very much.

Taking Notes

We have our frequencies and multipliers set where we want. This is very important.  I’m writing the settings down.  It’s extremely important to keep notes while you overclock. If the overclock is stable, write down the temperatures you get from running Prime95 and the CPU score from 3dmark.  If it fails, write that down.  We are going to be making a lot of settings changes.  If we don’t keep track, it will become overwhelming.

I’ll move over to Exit and choose Save and Exit and Ok.  To save and exit I can also press F10 on the keyboard from anywhere in the BIOS. I’ll press Pause-Break to stop the BIOS information screen and we can see the CPU is running at 3.2GHz and the RAM at 1282MHz.  I’ll press any key and let it boot into Windows.

Check Temps, Test for Stability and Benchmark the CPU

Let’s take a look at RealTemp. The idle temps are around 57C. Notice the multiplier is locked at 20x. The power saving features are turned off so it can’t go lower and the Turbo mode is off so it won’t go higher.  This is what we want while we are testing for stability, temperatures and performance.  We’ll use Prime95 on the large FFTs setting to find the load temperature. At 10 minutes the temp is around 85C degrees.  I’m writing down the minimum and maximum temperatures and the length of time Prime95 was running.

Next, I’ll close Prime95 and run 3dmark06 to benchmark the CPU. The CPU score at 3.2GHz is 6032.

So the system is stable at 3.2GHz.  In the next lesson, we’re going to continue pushing the CPU and see how far we can take it with the stock cooler.  Then we will replace the Intel cooler with a 3rd party cooler and see how fast the CPU can go with improved cooling.{/reg}