Basic Overclocking Guide for Intel C2D Processors

Overclock It!

Overclock It!

You should now have a basic understanding of what the values in your overclocking panel actually do. Let's look at the proper way to change these values safely.

BIOS External Clock

Increasing the external clock speed (FSB herein) will in turn also increase the speed of which your memory runs. To start off I suggest increasing this value in 25mhz increments until your computer is no longer stable or no longer boots. Once this happens back down the FSB 25mhz, adjust/tweak the options I am about to talk about, and then start raising the FSB in 5mhz increments until you loose stability or the computer no longer boots.

Changing (lowering) the CPU multiplier is not recommended on chips with multipliers of 9 or less unless you have a motherboard capable of running at very high FSB speeds. Lowering the multiplier does benefit you in the way of being able to run higher FSB and memory speeds for enhanced bandwidth and throughput but as of current most motherboards can't operate at FSB speeds high enough to take advantage of lowering the multiplier.


Setting your NB strap to your boards highest selectable value will greatly benefit you in running higher FSB/Memory speeds, so get this set pronto. Most Intel chipset based boards currently top out at 1066, and a few select boards have a maximum strap of 1333 which is even better.


Most motherboards by default will have the DRAM Spec set to DDR2 800 which is a divider of 2:3, making your RAM run as fast as it possibly can. This setting usually needs to be decreased in order for your RAM to stay within specification when higher FSB's are used.


I have found on my motherboard that I can achieve the highest stable overclock when my DRAM Spec is set to DDR 533 which is a 1:1 divider (the CPU and memory are running at the same speed). This allows me to increase the FSB without fear of topping out my RAM's max speed and also allowing me to tighten the RAM timings a bit because it's not running at it's maximum rated speed.

You will need to play with these options yourself as all motherboards perform differently with different dividers given what RAM is being used and how fast it is capable of operating. A quick google search should pull up enough information from other users who have tested all of the values to know which works best on your board.

BIOS Vcore

Setting a higher vcore value is another one of those almost sure-fire ways to help push the limits of your CPU's overclockability. Keep in mind that more voltage = more heat. You MUST have adequate CPU cooling in order to boost this value or else you risk damage to or complete failure of the CPU. All motherboards have a different range of selectable vcore values, and using more than 1.5v on good air cooling is not recommended (I personally ran 1.55vcore with a Scythe Infinity and never had a problem, evaluate your situation carefully and decided whether or not you can go above the 1.5v level). If you have a good watercooling setup the recommended maximum vcore is roughly 1.65v.

For TEC/Pelt users the maximum recommended vcore setting is around 1.7v and phase/cascade/dice/ln2 users should evaluate the cooling capacity of their units and adjust the maximum vcore accordingly.
BIOS Vdimm

Increasing the vdimm allows you to do a few things. The first thing being that your RAM can usually operate at a speed higher than what the manufacturer has rated. The second in some cases will also allow you to tighten your timings past what the manufacturer has specified. Most DDR2 modules will run at their peak performance level in the 2.2v area. Some IC's prefer more volts, and some less. I recommend testing what your RAM can do at 2.2v and going from their. If you plan on running your memory at a voltage higher than 2.2 make sure you have adequate cooling apparatus and good airflow as RAM is highly prone to problems when overheating.


Intel chipsets love extra voltage, it's what allows the chipset to run at extremely high FSB speeds. Upping this voltage is definitely recommended within reason. If you have a way to actively cool your chipset heatsink or have an aftermarket cooler you shouldn't have any problem maxing this voltage. If you are running the motherboards stock cooler a safe recommended value is 1.75v or less. I have rigged up a high speed 30mm fan over my chipset and feel that 2.0v is a safe value in my situation as the heatsink stays cool to the touch.

That's pretty much it! With the proper use of these settings you should be able to achieve a decent overclock depending on the quality of parts used in your system. Just try to remember to stay within reason when changing these settings. Also don't get frustrated easily if you can't instantly overclock to 4ghz especially if this is your first time overclocking. It takes time to figure out what settings works best for your setup, and everyones results will vary. Get used to what all of these settings control and the outcome of changing the given setting. Write down the outcomes if you have to so that you can remember what works and what doesn't work.

One last thing, don't forget to save your settings! ;)

BIOS Finished

If you have any questions, comments, or concerns please feel free to discuss them on our forum, thanks!
«Prev 1 2 3 4 5 Next»

Most Recent Comments


Register for the OC3D Newsletter

Subscribing to the OC3D newsletter will keep you up-to-date on the latest technology reviews, competitions and goings-on at Overclock3D. We won't share your email address with ANYONE, and we will only email you with updates on site news, reviews, and competitions and you can unsubscribe easily at any time.

Simply enter your name and email address into the box below and be sure to click on the links in the confirmation emails that will arrive in your e-mail shortly after to complete the registration.

If you run into any problems, just drop us a message on the forums.