The Intel Core i5 661 is pretty much an average processor. Aside from the Clarkdale architecture, which gives it integrated graphics capability, there’s nothing too extraordinary about this particular CPU. But wait, armed with water coolers, overclockers at the MSI Master Overclocking Arena (MOA) 2010 pushed its default 3,33 GHz clockspeed to 4,7 GHz – 4,8 GHz, and even 5 GHz or more! Such overclocking prowess has naturally prompted us to investigate further into this matter and try to find out the absolute limit of this processor. As with any other suicidal overclocking attempt, we shall show no mercy for the corresponding processor in the process.
Extreme overclocks needs a durable and reliable platform, so we built our rig out of a selection of good quality components that is likely able to withstand all the stress while providing us with ample tweaking opportunities. The complete specification is as follows:
CPU : Intel Core i5 661 ‘Clarkdale’, batch# L39B608
Motherboard : MSI Big Bang Fuzion
Memory : A-Data XPG DDR3-1866+ v2.0 ,1x2GB single channel
Graphics Card : GeForce 6200 256MB PCI
Hard Disk : WD Velociraptor 300GB
Power Supply : Antec TP Quattro 1200W OC Edition
Operating System : Windows 7 Ultimate 32-bit
CPU Cooling : K|ngp|n F1 EE Nickel Edition LN2 Container
Others : CoolerMaster Test Bench v1.0
Core i5 661 @ -150C
Like usual, we used Liquid Nitrogen (LN2) as our extreme cooling of choice. That way, it would be easier to get maximum overclocking results. Our core i5 works at very low temperatures. The MSI Big Bang Fuzion motherboard had previously been modified, making it capable of enduring the overclock at temperatures well below 130 degree Celsius. With 5 liters of LN2 by our side, we began our quest for the absolute, uppermost limit of Core i5 661.
Around 15 minutes after we started out, we managed to obtain an optimal setting for our system. The lowest temperature point at which our processor could still operate was -160 C. By pumping the VCore to 1,8 V (maximum allowed setting on the MSI Big Bang Fuzion Motherboard), our processor reached an impressive 6625 MHz, almost twice the default clockspeed of 3,33 GHz!
After submitting our result to the hardware database at Hwbot.org, we found our CPU sitting at the 10th position in the Core i5 661 category. Our score is still 300 MHz away from the current World Record holder. Unfortunately, our Big bang Fuzion motherboard would not allow us to pump the VCore beyond 1,8V. We’re quite certain that it could have reached at least 6,7 GHz or more, had we been able to supply the processor with 1,9 – 1,95 V of VCore. Therefore, we had to settle with 6625 MHz.
Just as we had predicted prior to the overclock, the Core i5 661 has an enormous overclocking potential. With the right setup, you can even expect to push this processor beyond 6 GHz or more. Far above its default clockspeed of 3,33 GHz. We’re not done with it just yet. In our second attempt, we will use even more LN2 along a motherboard which is able to supply more than 1,95V of VCore. Stay tuned to Jagat review for the next extreme overclocking updates!