Overclocking
Overclocking is the process of patiently tweaking advanced settings (Multpliers & Voltages) in the BIOS. Changing these settings can be done in a safe manner, however every overclock is different and the variables that work for one system can't be guaranteed to work for another. My goal is to help those new to overclocking learn how to overclock. This overclocking guide is specific to the Intel i7-920 processor, but the concepts involved work for nearly all processors. It is important to carefully change settings in the BIOS because some changes can permanently damage computer components (which would not be fun). Overclock at your own risk.
After a lot of trial and error I have been able to get my Intel i7-920 processor up to a stable 4.01Ghz overclock!!! What is even more amazing is that my Core Voltage is only at 1.264V! If the previous sentence didn't make sense, don't worry. This guide will get you up to speed on all the vocab that is needed to understand the settings in the BIOS.
Reading Assignments for Overclocking
I would recommend reading the following links to overclocking articles before changing any of the setting in BIOS:
1. An in-depth read of the i7-920 Architecture.
2. A great overclocking read specifically for the i7-920.
3. A super thread that explains some of the basic requirements & methods of overclocking.
After reading the above articles several times the instructions below will make a lot more sense.
Quick Prep Guide
1. Make sure that you know the current wattage of your system. If needed upgrade your power supply so that you will have plenty of overhead. It is also recommended to plug in an 8pin connector from your power supply to the motherboard on the 12v line (if your motherboard has an 8pin type) (It may only have a 4pin - in that case use the 4pin 12v connector).
2. Make sure you know how to clear your CMOS (if you're using the ASRock X58 Extreme then it is that little grey button on the back below the PS2 ports).
3. Make sure the stock temps of the processor at 2.66 ghz are below 45-50° centigrade when idle or below 65-70° under 100% load (download RealTemp)
4. Download CPU-ID and Prime95
5. It is optional - but updating the BIOS to the latest version is a smart thing to do. You can get the instant flash version from the ASRock website.
6. Make sure that your system is put together the way you like it. Meaning make sure you have all the parts you want/need installed (Windows and such)
7. Give yourself enough time. Finding the processors ideal overclock will definitely take several hours - it could even take several days.
Overclocking to a STABLE 4.01 Ghz
Stable is the keyword.
Ok so let me tell you my story. I started by reading a lot of different articles. The terminology was completely foreign, so it took a while to understand what the articles were explaining. Many of the settings in BIOS seemed dangerous and I was nervous about changing anything. In order to build up my courage I decided to start by flashing my BIOS to the lastest version (1.8) from the ASRock website and found the BIOS instant flash feature a breeze. That boosted my confidence. Then after getting a handle on the vocab I started dinking around with the BIOS overclocking settings. I tried a couple quick and dirty overclocks (basically boosting the Core Voltage and BCLK way high) and my computer would stall before getting to windows. It was a bit nerve wreaking the first time. But, luckily I had read enough to know that I needed to just simply clear the CMOS and restart the computer. Which of course reset the BIOS to factory defaults and the computer loaded right into windows.
After several more unsuccessful attempts at the quick and dirty, I decided to find out how far my i7-920 could go if I kept all the Voltages at their minimums and increased the Multipliers in little increments (Specifically the BCLK). But before we really go too far with how I reached my overlock - let's dive into some basics of overclocking.
Overclocking really only consists of three components:
1. Voltages
2. Multipliers
3. Testing
Although the BIOS lists the Multipliers at the top of the "OC Tweaker" tab, it is important to understand the Voltages of each component before dealing with any of the Multipliers. Before we go farther we need to define the vocab for Voltage and Multiplier perimeters.
Voltage Vocabulary Lesson
To help clear up the confusion around the overclocking jargon here is a quick break down of the voltage names in BIOS, their meanings, how the ASRock X58 Extreme board allows them to be altered, Intel recommended settings and the settings that worked for my overclock:
CPU Voltage - The voltage that controls the actual cores of the processor. This value should be equal to the uncore voltage (VTT) which will be defined below.
In the ASRock X58 Extreme BIOS this figure can be altered from 0.84375v - 2.00000v in increments of .00625v.
Intel recommends a max CPU Voltage of 1.55000v, However if you are using air cooling NEVER go over 1.35000v. Ideally you want to keep this number as low as possible. The higher the voltage the more heat is produced. So a lower voltage will not only increase the life of your processor, but does wonders on keeping temperatures low.
This is the value that you'd plug the VID from CPU-ID into - for my i7-920 I changed it to 1.2125v originally (based on the Core Voltage in CPU-ID of 1.216v) and found my max clock at stock VID at around 3.8 Ghz. To get up to 4.01 Ghz I had to increase the value up to 1.2750v - but I will explain that more in a bit.
If you are not able to get into windows - or your computer isn't loading - this is the first voltage that should be increased. Whatever value this is set to also change the uncore voltage (VTT) to.
Example: If CPU Voltage = 1.2125v then VTT voltage = 1.200v.
Example: If CPU Voltage = 1.2750v then VTT voltage = 1.270v.
DRAM Voltage - The voltage that effects the memory controller.
In the ASRock X58 Extreme BIOS this figure can be altered from 0.964v - 1.669v.
Intel STRONGLY advises not to go over 1.650v because it can damage the memory controller in the processor.
I kept it at the standard setting in BIOS of 1.564v during all my tests although I decided to bump it up to 1.654v because my memory is rated at 1.65v. Because my memory has LED's that indicate the load on the ram - I noticed that when I had the voltage set to 1.564v one stick of RAM was getting a workout - while the others just piddled around. After increasing it to 1.654v all three sticks of RAM began carrying an equal load.
IOH Voltage - The voltage of the North Bridge or NB, this helps with overclocking the QPI frequency. (PCI-E ports and such)
In the ASRock X58 Extreme BIOS it can be altered between 1.110v - 1.494v at an increment of 0.006v.
Intel Recommends to keep it below 1.300v.
I locked it at the standard of 1.110v.
VTT Voltage - Also known as the Uncore Voltage. It adjusts the voltage for the uncore side of the processor.
In the ASRock X58 Extreme BIOS it can be altered between 1.200v - 1.900v at an increment of 0.070v.
Intel recommends to keep it below 1.350v
I read that you should keep the VTT the same (or as close to the same as BIOS will let you) as the CPU Voltage. (I explained the relationship better under CPU Voltage definition). I currently have my VTT set to 1.270v to match my CPU Voltage of 1.27500v.
ICH Voltage - This is the voltage of the south bridge, which controls the hard drives.
In the ASRock X58 Extreme BIOS it can be altered between 1.16v - 1.56v at an increment of 0.02v.
Intel recommends to keep it below 1.30v.
I decided to keep it at the standard voltage of 1.16v
IOH CSI Voltage - This essentially controls the northbridge voltage (QPI).
In the ASRock X58 Extreme BIOS it can be altered between 1.16v - 1.56v in an increment of 0.02v.
I left it at the standard setting of 1.16v
IOH/ICH PCI-E Voltage - This is the voltage the board gives to PCI/PCI-E devices. This should be left at default unless you are changing the PCI-E ratio to anything higher than 100 (which isn't suggested because it could cause permanent damage on your PCI-E parts over time or very quickly depending on if it's anything over 105).
In the ASRock X58 Extreme BIOS it can be altered between 1.56v - 1.90v at an 0.02v increment.
Intel doesn't give recommendations on this component.
So I just left it at the standard setting of 1.56v.
CPU PLL Voltage - The PLL voltage is essentially the voltage applied to the CPU's internal clock distribution system.
In the ASRock X58 Extreme BIOS it can be altered between 1.86v - 2.50v at an increment of 0.02v.
Intel pretty much SCREAMS about keeping it below 1.88!!!.
I have it set at 1.86v because Intel's warnings scare me.
Multiplier Vocabulary Lesson
Much like the voltage vocab lesson, here is a break down of the the common multipliers. Following the same format they will be defined by name, meaning, ASRock X58 Extreme ranges, Intels recommended settings and the settings that worked for my overclock.
BCLK - The Base Frequency or Base Clock. All of the other multipliers are based on this frequency.
In the ASRock X58 Extreme BIOS it can be altered from 100Mhz - 300Mhz in an increment of 1Mhz. The standard or default is 133MHz.
Intel doesn't give a recommendation for this setting.
I set it to 191Mhz - and wouldn't recommend going over 205Mhz
PCI-E Frequency - Controls the frequency of the north bridge. This setting does not apply to overclocking the CPU and should be left at its default 100Mhz.
CPU Ratio Setting - CPU Multiplier. This number multiplied by the BCLK determines what speed your processor will overclock at.
CPU Frequency = BCLK x CPU Ratio Setting
For example - 4.01GHz CPU Frequency = 191Mhz BCLK x 21 CPU Ratio Setting
Or in other words - 191 times 21 = 4,011 (4.01Ghz)
In the ASRock X58 Extreme BIOS it can be altered from 12x - 21x the BCLK in an increment of 1x. The standard or default is 20x . Instructions on how to achieve 21x without turbo or speedstep enabled are below.
Intel doesn't give a recommendation for this setting.
I have it set to 21x the BLCK.
QPI Frequency - QPI Multiplier. This determines the speed between the processor and the chipset.
In the ASRock X58 Extreme BIOS it there will be three settings listed. Each setting is listed at 18x, 20x, 24x the BCLK.
Intel doesn't have a recommended setting.
I would keep it at the lowest setting of 18x the BCLK - this is also the standard setting.
Uncore Frequency - Uncore Multiplier. This is the frequency of the Memory Controller and the 8mb L3 cache.
In the ASRock X58 Extreme BIOS it can be altered from 16x - 42x the BCLK.
Intel recommends keeping the Uncore Frequency as least 2 times higher than the DRAM Frequency.
I kept the setting on its lowest setting of 16x the BCLK and made sure my DRAM was set at 8x the BCLK.
DRAM Frequency - Frequency of the DDR3 Ram Modules.
In the ASRock X58 Extreme BIOS it can be altered from 6x - 16x the BCLK in an increment of 2x. The standard or default is either 6x or 8x the BCLK.
Intel doesn't have a recommendation for this setting.
I set my DRAM Frequency at 8x so that it was half of the Uncore Frequency of 16x the BCLK.
Finally - How to Overclock
Now that we have discussed all the settings and vocabulary we can move on to the actual overclocking! Feel free to reference the definitions above at any time.
The first thing I needed to know was my VID (or stock Core Voltage) so that I could use that as my "CPU Voltage" in BIOS (on the "OC Tweaker" tab). I found my VID by going into the BIOS and restoring the defaults (you can restore defaults on the "Exit" tab in BIOS). After restoring the defaults I went into the "OC Tweaker" tab and disabled "Spread Spectrum" and changed the setting for "ASRock VDroop Control" to "Without VDroop". I then went into the "Advanced" tab and under "CPU Settings", increased the "CPU Ratio Setting" to 21 (by using the + or - button on the keypad), and then disabled "SpeedStep". After disabling "SpeedStep" the "Turbo Mode" option disapeared - but the "CPU Ratio Setting" stayed at 21 (which is exactly what I was going for). And I was like "Oh Yeah!!" Here is a BIOS screen shot of what it looked like:
![Image]()
After adjusting a couple other settings in BIOS (like Chipset Settings from PCI to PCI Express and Boot order) I saved the changes and loaded into Windows 7. When I got into Windows 7 I loaded up CPU-ID (CPU-Z). CPU-ID looked like this:
![Image]()
Because I had set the CPU Ratio to 21 and the BCLK Frequency in BIOS was set to the stock 133, the Core Speed in CPU-ID was showing 2800 MHz (2.8 GHz Overclock).
BCLK 133 x CPU Ratio 21 = 2,793 MHz or simply put 2.80 Ghz
More important than the slight overlock was that I discovered that my Core Voltage was resting at 1.216v in CPU-ID. The Core Voltage of 1.216v was the VID for my CPU Voltage in BIOS. Now I was ready to go into BIOS and have some fun!!
Testing - Trial and Error
Heading into the BIOS I decided to find how far I could increase my BCLK at the Core Voltage setting of 1.216v. I simply increased the BCLK by 10, saved the changes and loaded into windows. After running CPU-ID to make sure everything looked stable, I went back into the BIOS and increased it another 10 increments. I continued to follow this process of trial and error until I couldn't load into windows. I started to have trouble loading into windows when I reached a BCLK of about 181.
After finding the point that the computer could no longer load into windows I started to decrease the BCLK in increments of 1. Stepping back to a BCLK of about 179 I found that I could load into windows again. The next step was to test the stability of the overclock using a tool called Prime-95. Prime-95 puts the CPU through a series of torture tests. The tests will not harm the CPU, but they will help show weaknesses in the stability of the system. When I ran Prime-95 on a BCLK of 179 it failed horribly - BSOD (blue screen of death).
I then went back into the BIOS and changed the BCLK to 178. The computer was able to make it into windows but continued to fail the Prime-95 torture test. I continued to repeat the process until I finally came to the BCLK of 172. At this setting Prime-95 would run through all the tests and was a very stable overclock. What this meant however was that my overclock was only at 3.60 Ghz.
BCLK 172 x CPU Ratio 21 = 3,612 MHz or simply put 3.60 Ghz
I concluded that at the VID of 1.216v the max stable overclock I would be able to achieve would be 3.60 Ghz. While that achievement alone is pretty fantastic, I wasn't satisfied yet. I knew that if I increased the CPU voltage a bit more then I would be able to increase the clock speed even more. I went back into the BIOS and increase the Core Voltage to 1.2750v (which was only one step up). I knew that increasing the Core Voltage would increase the heat of the processor so I didn't want to step any higher than I had to. I repeated the steps for finding the overclock on the original VID by increasing the BCLK until my system wouldn't load into windows, and then little by little scaling back. I was able to load into windows at a BCLK of 202 (which is equivalent to a 4.24 GHz overclock) but the system wouldn't pass tests in Prime-95.
I continued to scale back the BCLK until I reached 191. At a BCLK of 191 I could let Prime-95 run 24-7 and I wouldn't have any hicups. So my end result was an overclock of 4.01 Ghz!
BCLK 191 x CPU Ratio 21 = 4,011 MHz or simply put 4.01 Ghz
Conclusion
In conclusion, overclocking is really not that difficult. Yes there are scary times when the computer freaks out, but for the most part everything comes right back up. It feels great after achieving a stable overclock because it feels as though you have become one with the processor.
I hope that this guide has been informative or that at least those that have an i7-920 processor and ASRock X58 Extreme motherboard will find it useful. Here is the parting picture - a screen shot of CPU-ID showing my overclock results.
![Image]()
Overclocking is the process of patiently tweaking advanced settings (Multpliers & Voltages) in the BIOS. Changing these settings can be done in a safe manner, however every overclock is different and the variables that work for one system can't be guaranteed to work for another. My goal is to help those new to overclocking learn how to overclock. This overclocking guide is specific to the Intel i7-920 processor, but the concepts involved work for nearly all processors. It is important to carefully change settings in the BIOS because some changes can permanently damage computer components (which would not be fun). Overclock at your own risk.
After a lot of trial and error I have been able to get my Intel i7-920 processor up to a stable 4.01Ghz overclock!!! What is even more amazing is that my Core Voltage is only at 1.264V! If the previous sentence didn't make sense, don't worry. This guide will get you up to speed on all the vocab that is needed to understand the settings in the BIOS.
Reading Assignments for Overclocking
I would recommend reading the following links to overclocking articles before changing any of the setting in BIOS:
1. An in-depth read of the i7-920 Architecture.
2. A great overclocking read specifically for the i7-920.
3. A super thread that explains some of the basic requirements & methods of overclocking.
After reading the above articles several times the instructions below will make a lot more sense.
Quick Prep Guide
1. Make sure that you know the current wattage of your system. If needed upgrade your power supply so that you will have plenty of overhead. It is also recommended to plug in an 8pin connector from your power supply to the motherboard on the 12v line (if your motherboard has an 8pin type) (It may only have a 4pin - in that case use the 4pin 12v connector).
2. Make sure you know how to clear your CMOS (if you're using the ASRock X58 Extreme then it is that little grey button on the back below the PS2 ports).
3. Make sure the stock temps of the processor at 2.66 ghz are below 45-50° centigrade when idle or below 65-70° under 100% load (download RealTemp)
4. Download CPU-ID and Prime95
5. It is optional - but updating the BIOS to the latest version is a smart thing to do. You can get the instant flash version from the ASRock website.
6. Make sure that your system is put together the way you like it. Meaning make sure you have all the parts you want/need installed (Windows and such)
7. Give yourself enough time. Finding the processors ideal overclock will definitely take several hours - it could even take several days.
Overclocking to a STABLE 4.01 Ghz
Stable is the keyword.
Ok so let me tell you my story. I started by reading a lot of different articles. The terminology was completely foreign, so it took a while to understand what the articles were explaining. Many of the settings in BIOS seemed dangerous and I was nervous about changing anything. In order to build up my courage I decided to start by flashing my BIOS to the lastest version (1.8) from the ASRock website and found the BIOS instant flash feature a breeze. That boosted my confidence. Then after getting a handle on the vocab I started dinking around with the BIOS overclocking settings. I tried a couple quick and dirty overclocks (basically boosting the Core Voltage and BCLK way high) and my computer would stall before getting to windows. It was a bit nerve wreaking the first time. But, luckily I had read enough to know that I needed to just simply clear the CMOS and restart the computer. Which of course reset the BIOS to factory defaults and the computer loaded right into windows.
After several more unsuccessful attempts at the quick and dirty, I decided to find out how far my i7-920 could go if I kept all the Voltages at their minimums and increased the Multipliers in little increments (Specifically the BCLK). But before we really go too far with how I reached my overlock - let's dive into some basics of overclocking.
Overclocking really only consists of three components:
1. Voltages
2. Multipliers
3. Testing
Although the BIOS lists the Multipliers at the top of the "OC Tweaker" tab, it is important to understand the Voltages of each component before dealing with any of the Multipliers. Before we go farther we need to define the vocab for Voltage and Multiplier perimeters.
Voltage Vocabulary Lesson
To help clear up the confusion around the overclocking jargon here is a quick break down of the voltage names in BIOS, their meanings, how the ASRock X58 Extreme board allows them to be altered, Intel recommended settings and the settings that worked for my overclock:
CPU Voltage - The voltage that controls the actual cores of the processor. This value should be equal to the uncore voltage (VTT) which will be defined below.
In the ASRock X58 Extreme BIOS this figure can be altered from 0.84375v - 2.00000v in increments of .00625v.
Intel recommends a max CPU Voltage of 1.55000v, However if you are using air cooling NEVER go over 1.35000v. Ideally you want to keep this number as low as possible. The higher the voltage the more heat is produced. So a lower voltage will not only increase the life of your processor, but does wonders on keeping temperatures low.
This is the value that you'd plug the VID from CPU-ID into - for my i7-920 I changed it to 1.2125v originally (based on the Core Voltage in CPU-ID of 1.216v) and found my max clock at stock VID at around 3.8 Ghz. To get up to 4.01 Ghz I had to increase the value up to 1.2750v - but I will explain that more in a bit.
If you are not able to get into windows - or your computer isn't loading - this is the first voltage that should be increased. Whatever value this is set to also change the uncore voltage (VTT) to.
Example: If CPU Voltage = 1.2125v then VTT voltage = 1.200v.
Example: If CPU Voltage = 1.2750v then VTT voltage = 1.270v.
DRAM Voltage - The voltage that effects the memory controller.
In the ASRock X58 Extreme BIOS this figure can be altered from 0.964v - 1.669v.
Intel STRONGLY advises not to go over 1.650v because it can damage the memory controller in the processor.
I kept it at the standard setting in BIOS of 1.564v during all my tests although I decided to bump it up to 1.654v because my memory is rated at 1.65v. Because my memory has LED's that indicate the load on the ram - I noticed that when I had the voltage set to 1.564v one stick of RAM was getting a workout - while the others just piddled around. After increasing it to 1.654v all three sticks of RAM began carrying an equal load.
IOH Voltage - The voltage of the North Bridge or NB, this helps with overclocking the QPI frequency. (PCI-E ports and such)
In the ASRock X58 Extreme BIOS it can be altered between 1.110v - 1.494v at an increment of 0.006v.
Intel Recommends to keep it below 1.300v.
I locked it at the standard of 1.110v.
VTT Voltage - Also known as the Uncore Voltage. It adjusts the voltage for the uncore side of the processor.
In the ASRock X58 Extreme BIOS it can be altered between 1.200v - 1.900v at an increment of 0.070v.
Intel recommends to keep it below 1.350v
I read that you should keep the VTT the same (or as close to the same as BIOS will let you) as the CPU Voltage. (I explained the relationship better under CPU Voltage definition). I currently have my VTT set to 1.270v to match my CPU Voltage of 1.27500v.
ICH Voltage - This is the voltage of the south bridge, which controls the hard drives.
In the ASRock X58 Extreme BIOS it can be altered between 1.16v - 1.56v at an increment of 0.02v.
Intel recommends to keep it below 1.30v.
I decided to keep it at the standard voltage of 1.16v
IOH CSI Voltage - This essentially controls the northbridge voltage (QPI).
In the ASRock X58 Extreme BIOS it can be altered between 1.16v - 1.56v in an increment of 0.02v.
I left it at the standard setting of 1.16v
IOH/ICH PCI-E Voltage - This is the voltage the board gives to PCI/PCI-E devices. This should be left at default unless you are changing the PCI-E ratio to anything higher than 100 (which isn't suggested because it could cause permanent damage on your PCI-E parts over time or very quickly depending on if it's anything over 105).
In the ASRock X58 Extreme BIOS it can be altered between 1.56v - 1.90v at an 0.02v increment.
Intel doesn't give recommendations on this component.
So I just left it at the standard setting of 1.56v.
CPU PLL Voltage - The PLL voltage is essentially the voltage applied to the CPU's internal clock distribution system.
In the ASRock X58 Extreme BIOS it can be altered between 1.86v - 2.50v at an increment of 0.02v.
Intel pretty much SCREAMS about keeping it below 1.88!!!.
I have it set at 1.86v because Intel's warnings scare me.
Multiplier Vocabulary Lesson
Much like the voltage vocab lesson, here is a break down of the the common multipliers. Following the same format they will be defined by name, meaning, ASRock X58 Extreme ranges, Intels recommended settings and the settings that worked for my overclock.
BCLK - The Base Frequency or Base Clock. All of the other multipliers are based on this frequency.
In the ASRock X58 Extreme BIOS it can be altered from 100Mhz - 300Mhz in an increment of 1Mhz. The standard or default is 133MHz.
Intel doesn't give a recommendation for this setting.
I set it to 191Mhz - and wouldn't recommend going over 205Mhz
PCI-E Frequency - Controls the frequency of the north bridge. This setting does not apply to overclocking the CPU and should be left at its default 100Mhz.
CPU Ratio Setting - CPU Multiplier. This number multiplied by the BCLK determines what speed your processor will overclock at.
CPU Frequency = BCLK x CPU Ratio Setting
For example - 4.01GHz CPU Frequency = 191Mhz BCLK x 21 CPU Ratio Setting
Or in other words - 191 times 21 = 4,011 (4.01Ghz)
In the ASRock X58 Extreme BIOS it can be altered from 12x - 21x the BCLK in an increment of 1x. The standard or default is 20x . Instructions on how to achieve 21x without turbo or speedstep enabled are below.
Intel doesn't give a recommendation for this setting.
I have it set to 21x the BLCK.
QPI Frequency - QPI Multiplier. This determines the speed between the processor and the chipset.
In the ASRock X58 Extreme BIOS it there will be three settings listed. Each setting is listed at 18x, 20x, 24x the BCLK.
Intel doesn't have a recommended setting.
I would keep it at the lowest setting of 18x the BCLK - this is also the standard setting.
Uncore Frequency - Uncore Multiplier. This is the frequency of the Memory Controller and the 8mb L3 cache.
In the ASRock X58 Extreme BIOS it can be altered from 16x - 42x the BCLK.
Intel recommends keeping the Uncore Frequency as least 2 times higher than the DRAM Frequency.
I kept the setting on its lowest setting of 16x the BCLK and made sure my DRAM was set at 8x the BCLK.
DRAM Frequency - Frequency of the DDR3 Ram Modules.
In the ASRock X58 Extreme BIOS it can be altered from 6x - 16x the BCLK in an increment of 2x. The standard or default is either 6x or 8x the BCLK.
Intel doesn't have a recommendation for this setting.
I set my DRAM Frequency at 8x so that it was half of the Uncore Frequency of 16x the BCLK.
Finally - How to Overclock
Now that we have discussed all the settings and vocabulary we can move on to the actual overclocking! Feel free to reference the definitions above at any time.
The first thing I needed to know was my VID (or stock Core Voltage) so that I could use that as my "CPU Voltage" in BIOS (on the "OC Tweaker" tab). I found my VID by going into the BIOS and restoring the defaults (you can restore defaults on the "Exit" tab in BIOS). After restoring the defaults I went into the "OC Tweaker" tab and disabled "Spread Spectrum" and changed the setting for "ASRock VDroop Control" to "Without VDroop". I then went into the "Advanced" tab and under "CPU Settings", increased the "CPU Ratio Setting" to 21 (by using the + or - button on the keypad), and then disabled "SpeedStep". After disabling "SpeedStep" the "Turbo Mode" option disapeared - but the "CPU Ratio Setting" stayed at 21 (which is exactly what I was going for). And I was like "Oh Yeah!!" Here is a BIOS screen shot of what it looked like:
After adjusting a couple other settings in BIOS (like Chipset Settings from PCI to PCI Express and Boot order) I saved the changes and loaded into Windows 7. When I got into Windows 7 I loaded up CPU-ID (CPU-Z). CPU-ID looked like this:
Because I had set the CPU Ratio to 21 and the BCLK Frequency in BIOS was set to the stock 133, the Core Speed in CPU-ID was showing 2800 MHz (2.8 GHz Overclock).
BCLK 133 x CPU Ratio 21 = 2,793 MHz or simply put 2.80 Ghz
More important than the slight overlock was that I discovered that my Core Voltage was resting at 1.216v in CPU-ID. The Core Voltage of 1.216v was the VID for my CPU Voltage in BIOS. Now I was ready to go into BIOS and have some fun!!
Testing - Trial and Error
Heading into the BIOS I decided to find how far I could increase my BCLK at the Core Voltage setting of 1.216v. I simply increased the BCLK by 10, saved the changes and loaded into windows. After running CPU-ID to make sure everything looked stable, I went back into the BIOS and increased it another 10 increments. I continued to follow this process of trial and error until I couldn't load into windows. I started to have trouble loading into windows when I reached a BCLK of about 181.
After finding the point that the computer could no longer load into windows I started to decrease the BCLK in increments of 1. Stepping back to a BCLK of about 179 I found that I could load into windows again. The next step was to test the stability of the overclock using a tool called Prime-95. Prime-95 puts the CPU through a series of torture tests. The tests will not harm the CPU, but they will help show weaknesses in the stability of the system. When I ran Prime-95 on a BCLK of 179 it failed horribly - BSOD (blue screen of death).
I then went back into the BIOS and changed the BCLK to 178. The computer was able to make it into windows but continued to fail the Prime-95 torture test. I continued to repeat the process until I finally came to the BCLK of 172. At this setting Prime-95 would run through all the tests and was a very stable overclock. What this meant however was that my overclock was only at 3.60 Ghz.
BCLK 172 x CPU Ratio 21 = 3,612 MHz or simply put 3.60 Ghz
I concluded that at the VID of 1.216v the max stable overclock I would be able to achieve would be 3.60 Ghz. While that achievement alone is pretty fantastic, I wasn't satisfied yet. I knew that if I increased the CPU voltage a bit more then I would be able to increase the clock speed even more. I went back into the BIOS and increase the Core Voltage to 1.2750v (which was only one step up). I knew that increasing the Core Voltage would increase the heat of the processor so I didn't want to step any higher than I had to. I repeated the steps for finding the overclock on the original VID by increasing the BCLK until my system wouldn't load into windows, and then little by little scaling back. I was able to load into windows at a BCLK of 202 (which is equivalent to a 4.24 GHz overclock) but the system wouldn't pass tests in Prime-95.
I continued to scale back the BCLK until I reached 191. At a BCLK of 191 I could let Prime-95 run 24-7 and I wouldn't have any hicups. So my end result was an overclock of 4.01 Ghz!
BCLK 191 x CPU Ratio 21 = 4,011 MHz or simply put 4.01 Ghz
Conclusion
In conclusion, overclocking is really not that difficult. Yes there are scary times when the computer freaks out, but for the most part everything comes right back up. It feels great after achieving a stable overclock because it feels as though you have become one with the processor.
I hope that this guide has been informative or that at least those that have an i7-920 processor and ASRock X58 Extreme motherboard will find it useful. Here is the parting picture - a screen shot of CPU-ID showing my overclock results.
