Why is Ivy Bridge so hot? Ask that question in any forum currently, and you are likely to receive one of two different popular (but not entirely correct) answers that everyone has been parroting:
The first answer is correct, but wrong at the same time – power density is greater, but it isn’t what is causing temperatures to be as much as 20 °C higher on Ivy Bridge compared to Sandy Bridge when overclocked. The second answer is jumping to conclusions without sufficient evidence. If you aren’t in the loop, there’s evidence of a considerable temperature difference nearly everywhere you look – we confirmed it by mirroring settings in our Ivy Bridge review, and we have read similar reports in solid testing at Anandtech as well as from other sites.
- “Power density is greater on Ivy Bridge than Sandy Bridge”
- “Intel has problems with tri-gate/22nm”
So why is Ivy Bridge hot? Intel is using TIM paste between the Integrated Heat Spreader (IHS) and the CPU die on Ivy Bridge chips, instead of fluxless solder.
How does TIM paste generally compare with fluxless solder for conducting heat? Heat conductivity can be measured in watts per meter Kelvin. To be technically exact, we would need to know exactly what Intel is using for TIM paste/solder. When I went to Intel and asked, their polite answer may not surprise you – “Secret sauce”! Given that, we can use some rough approximations. A solder attach could have a heat conductivity in the range of 80 W/mK. A TIM paste could have a heat conductivity in the range of 5 W/mK. That’s your problem right there! Note that these values are not exact, as we don’t know the exact heat conductivity of Intel’s “Secret sauce”. However, these are values representative of solder or TIM paste, and there is a giant gap between how TIM paste and solder perform in regards to conducting heat. They are in different leagues.
Read the full article over on Overclockers.
I've read one comment somewhere that Intel could be doing this as a cost-cutting measure teamed with the (unfortunate) fact that AMD are no longer a serious threat to them, so they can do whatever the hell they want. I'll just say that I'm glad I've got a Sandy Bridge CPU here...