Goals

The variety of users reading this guide is vast, and each user’s goal will be unique and specific to his/her needs.  It would be impossible for me to address every user’s specific needs.  But I’ve attempted to be as broad, yet specific as possible.  My goal is to assist the maximum number of users as possible, despite your specific needs.

Based on user feedback from the previous version of this guide, I decided to better address overclocking with power features enabled.  The easy answer was to follow the old guide and then attempt to enable your power features afterward, but that rarely worked when approaching the limits of a given system.

Just as before, if you want to maximize your overclock, you should disable all the power saving features in the BIOS as detailed in step 1.  However, if you’re after a more moderate overclock, and you’d like to save power (especially while your system sits idle) you can leave those setting enabled.  Just follow the guide as written (I’ve added tips for you along the way) to find your best settings.  While your potential overclock will be more limited, the bennefit will likely be worth it to many of you.

Terminology

I’d like to start off by writing briefly about the BIOS and more specifically, differences in terminology between the different manufacturers.  Obviously there are too many motherboards on the market to show you every single one in this guide.  But looking at boards from the four top manufactures, we should be able to better identify specific terminologies used by each.

Below I’ve created a table comparing the terminology used by the four major enthusiast motherboard manufacturers.

A comparison of BIOS terminology used by four top manufacturers

***A brief note about Asus.  Asus makes multipliers a little more confusing in this guide because the BIOS doesn’t show the ratios at all, they only show the speed of the item based on the bclock set.  This requires a little additional math on your part while using this guide.  Please be aware of this difference as you progress***

Throughout this guide, I’ll be referring to the terminology used by Gigabyte because it is most familiar to me.  This top section is to be used for reference so that you know what I’m referring to you when your BIOS options don’t match my instructions.

Understanding “total system performance”

Before we go into how we overclock these CPU’s let us look at what determines how fast your whole system will run.  CPU frequency is very important.  However, there are many other factors that play into your total system performance.  All of your primary BIOS overclocking revolves around the Base Clock or “bclock” and clock ratios.  The base clock’s default speed for all P55/H55/H57 based systems is 133MHz.  Typically we shoot for overclocks in the range of 200MHz bclock….doing that has a major effect on a number of things…

A map of the Clarkfield dice

CPU frequency = bclock x CPU clock ratio

The CPU speed is the primary concern for day to day and very noticeable performance gains can be attained by overclocking the CPU.  Looking at the picture above, the CPU speed refers to the actual speed that the chip on the right operates at.

QPI frequency = bclock x QPI clock ratio

Actually on the Clarkdale processor, the two pieces of silicon are linked by the MCP interface, the confusing part about that in our motherboard’s BIOS’s and in CPU-Z, is that the MCP link as erroneously referred to as a Quick Path Interface or “QPI”.  But rest assured, the QPI settings listed in your BIOS refers to the MCP interconnect between the two chips on your processor.  The misnaming continues due to the fact that another chip shares this platform with Clarkdale…..the Lynnfield based quad core CPUs….they used QPI and they were here first!

So what about it?  Well, EVERYTHING….everything in your system has to communicate with the CPU via this link, even the memory.  If you’re familiar with LGA775 based systems, they worked in a very similar fashion except the chip on the left in the image above was located on the motherboard, and was called the “Northbridge” and had to communicate with the CPU via the front side bus or “FSB”.  Well, just as in those LGA775 based systems where increasing FSB frequency had a major impact on performance, the same rule applies here.  So maximizing the MCP frequency is very important.  From this point forward, I will refer to the MCP link speed as the “QPI freq” to avoid confusion while working in your BIOS and/or CPU-Z.

Memory frequency = bclock x System Memory Multiplier (SPD)

Memory is shown in the BIOS as a multiplier of 6, 8, 10, etc…  This represents the multiplier to reach the DDR speed.  So, a stock 133MHz bclock with the multiplier of 8 would result in a memory speed of DDR3-1066.

DDR – The other part that can be quite confusing for users who are not familiar with DDR technology is the difference between the memory clock speed and the memory’s DDR speed.  For instance, DDR3-1600 actually runs at 800MHz, it’s just that DDR (or dual data rate) technology allows the memory to process twice per clock cycle.  Back when we switched technologies from SDRAM to DDR for the first time, the manufacturers started saying DDR-400 when it ran at 200MHz because it was better marketing to sell their memory over the older SDRAM technology.  This is why CPU-Z shows 800MHz for your DDR3-1600, or 1000MHz for your DDR3-2000.

Memory speed and bandwidth can have a huge effect in some applications, and negligible impact on others.  But overall, top shelf memory is one of the worse items you can spend your money on from a value perspective.  Faster CPUs and GPUs will give you much more performance for your hard earned cash.

iGPU frequency = (set iGPU freq) x (set bclock freq) / 133

In the BIOS of most motherboards, the iGPU frequency setting is based on the default bclock frequency.  This means that an iGPU frequency that is set at 900MHz in the BIOS, will only actually be 900MHz if the bclock frequency is set to 133MHz, if the bclock frequency was raised by 25% to 166MHz, the actual iGPU frequency would also go up by 25% or 1125MHz.  This is a relatively simple concept to understand, except that YOU have to do the calculation, because the BIOS only report the set frequency, not the actual frequency.

As time goes on and the BIOS’s get better, support for overclocking with these systems will get better.  Already it appears that Asus have additional support in some of their BIOS revisions which make this equation and extra math unnecessary.  But I have not had any hand-on experience with it, you’ll have to aces the situation based on your BIOS options.

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