Back in April, there came out a report from Overclockers.net claiming that Intel used thermal paste instead of solder in Ivy Bridge, which explains why the chips run so much hotter than Sandy Bridge processors do. Overclockers didn't do any testing, though, they just shared the fact that Intel uses thermal paste instead of solder. Well, a Japanese website decided to do some testing, and they have confirmed that the thermal paste is indeed the issue.
The Japanese-to-English translation is a little rough, so bear with me. It looks like the testers used an Intel Core i7-3770K for the test. They removed the heatspreader, saw the thermal paste that Intel used, and decided to change that out for some of their own. It looks as though they used OCZ's "Freeze Extreme" with a thermal conductivity rating of 82.0W/mk, which is quite extreme. They also tried Coollaboratory's "Liquid Pro" thermal paste, which is rated even higher but has a couple drawbacks (such as corrosion).
From there data, there was a remarkable improvement. Up to 11° C for their tests at a standard clock, and 20° C in their overclocking test. Overclockability also improved, and they got the processor up to 5GHz at 1.55V. That's pretty amazing, considering all they did was change the thermal paste. Removing the heatspreader may be easy, but it voids your warranty, so don't just go doing this willy-nilly. There's a chance you could break your CPU, so make sure take that into consideration before you do it.
If you want to read the full article in all its Japanese glory, head on over to the website. If you're in Chrome or IE (not sure about Firefox), the browser will ask you if you'd like to have the page translated. It's rough, but you can get the main parts of what they're saying.