Overclocking Testing and Results
Now this is where we spent most of our time with the new K-series CPUs. Overclocking with these parts turned out to be a pretty fruitful experience and proved that Intel is still on the top of its game when it comes to process technology and frequency headroom.

For my testing I was only using some moderate air cooling that included an ambient air temperature of around 75 degrees and a Thermaltake fan that we have been using for over a year now. The first processor on the chopping block was the dual-core i5-655K and I was blown away with the results.

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All I did was enter into the BIOS, set a voltage I was comfortable with (in this case 1.45v) and started increasing the Turbo Mode multiplier from its default of 26x…and then kept increasing it. In fact I was able to hit a 36x multiplier on the dual-core multiplier!

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You are looking at that correctly – I was able to take the i5-655K from the base frequency of 3.2 GHz to 4.8 GHz without really a sweat! The system was stable, running for several hours with all four threads loaded while keeping temperatures high, but within reasonable limits considering the cooling configuration I was using.

My time with the Core i7-875K was a bit more work with four different multipliers to adjust (1-4 cores active) I wanted to find the top for each of them that was stable. I was using the same motherboard and cooling but topped out at noticeably lower frequencies.

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With just a single core load I was able to move the CPU from 3.6 GHz to 4.26 GHz – a healthy gain but not something we haven’t been seen before on other Lynnfield processors. The 4 core results were just about able to 4.0 GHz:

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Again, this is a pretty solid overclock of the Core i7-875K, and it was reached without too much of an issue but I did expect a little more. Maybe that was just because I was overclocking the Core i5-655K first and the new 32nm core had me spoiled.

Either way, the new Intel K-series of parts with their unlocked multipliers for memory, core and Turbo modes made the overclocking experience easier and more enjoyable. By enabling the user to completely remove bottlenecks from overclocking scenarios, and not requiring a $1000 CPU to do it, Intel has just made quite a few enthusiasts happy.


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