During the launch of Intel's Ivy Bridge processors, it turned out that the processors were harder to keep cool than their Sandy Bridge predecessors. Late April, we reported that this was possibly caused by the chip being smaller with as a result heat being concentrated on a smaller surface. It was revealed that Intel had used thermal paste in the chips, instead of electrical non-conducting solder.
The Japanese website Impress PC Watch has since removed the Integrated Heatspreader (IHS) of an Intel Core i7-3770K processor and put it to the test. The white substance has been scraped off and replaced with OCZ thermal paste. The test was then repeated with Coollaboratory paste. According to the specifications, this Coollaboratory Liquid Pro thermal paste has a thermal conductivity of 82 watt per metre Kelvin (W/mK). The CPU cooler that was used is Thermalright's Silver Arrow SB-E, which features eight 6 millimetre heat pipes and both a 140 mm and 150 mm fan.
Replacing the thermal paste reduced the temperature of the Core i7-3770K at reference speeds, as proven by the temperature drop of 8 degrees Celsius when using the OCZ Freeze Extreme. The Liquid Pro kept the chip three degrees cooler even.
Impress PC Watch obviously overclocked the chip, opting for a frequency of 4.6 GHz. The temperature of the processor was about 15 degrees lower with the Freezer Pro and a remarkable 20 degrees lower when using the Liquid Pro thermal paste. This left them wanting more, so the chip's frequency was increased to 5 GHz, combined with a 1.55V voltage. Even at this speed, the processor retained its stability, unaffected by temperature.
While the temperatures are dependent on the used CPU cooler, the test showed that substituting the thermal paste had a positive effect on heat production. It has to be noted that the warranty of the processor is voided if you remove the heatspreader.
It's peculiar that the Ivy Bridge chips perform worse compared to Sandy Bridge processors at higher clock frequencies. The decision to substitute the solder for inferior thermal paste is quite perplexing, especially given the fact that we're not talking about entry-level Celeron or Pentium chips, but K-series processors for enthusiasts seeking to get the most performance out of their chips thanks to the unlocked multiplier. It is rumoured that Intel has done this purposely to get rid of Sandy Bridge supply, but we cannot confirm this. At the time of writing, Intel has yet to respond.
Image source: Impress PC Watch