Ivy Bridge Running Hotter Than Intel's Last-gen CPU

crookedvulture writes "The launch of Intel's Ivy Bridge CPUs made headlines earlier this week, but the next-gen processor's story is still being told. When overclocked, Ivy Bridge runs as much as 20C hotter than its Sandy Bridge predecessor at the same speed, despite the fact that the two chips have comparable power consumption. There are several reasons for these toasty tendencies. The new 22-nm process used to fabricate the CPU produces a smaller die with less surface area to dissipate heat. Intel has changed the thermal interface material between the CPU die and its heat spreader. Ivy also requires a much bigger step up in voltage to hit the same speeds as Sandy Bridge."

Comments

notice the "when overclocked" caveat

[Trepidity]

It's clear in the article, but the headline here sort of implies that the chips run hotter in general, whereas this test is only saying the new chips run hotter when overclocked. From what I can find, when run at the rated voltages/speeds, Ivy Bridge CPUs run at about the same temperature as last gen's CPUs.

Re:notice the "when overclocked" caveat

[Alastor187]

It's clear in the article, but the headline here sort of implies that the chips run hotter in general, whereas this test is only saying the new chips run hotter when overclocked. From what I can find, when run at the rated voltages/speeds, Ivy Bridge CPUs run at about the same temperature as last gen's CPUs.

Seems like that would make sense if at normal 'voltage/speed' the Ivy Bridge is using less power. Based on the the numbers in the link the Ivy Bridge has a higher overall thermal resistance, junction-to-air, of roughly 30% [=((100C-20C)/(80C-20C))*(231W/236W)]. Based on other reviews the Ivy Bridge processors uses less power at stock frequency/voltage so that may be offsetting much of the temperature rise due to an increase in package resistance and heatsink interface resistance, under normal conditions.

Power dissipation increases exponential with increases in frequency/voltage and it appears to rise faster with the Ivy Bridge processors. So as the power dissipation approaches or exceeds that of the Sandy Bridge processor much higher processor temperatures will be measured in the Ivy Bridge because of the higher thermal resistances.

I think this is a non-issue for the average consumer. However, overclockers would probably be better off with the Sandy Bridge hardware.

Re:3d tri-gate not as good as promised

[gstrickler]

Read the Anandtech review, that's total system power consumption. If you compare just the CPU power consumption it's ~33% more power efficient (66W increase from idle to load for Ivy Bridge vs 98W increase for SB). And if you look at the GPU intensive comparisons, IB is ~20% more power efficient, but that's including a ~33% increase in GPU cores and an increase in GPU clock, for an ~40% increase in performance while using 20% less power. For the first generation chips on a brand new production process, those are very good results. I expect to see them improve as their 22nm tri-gate process matures.

Hotter != more heat

[Ken_g6]

After switching all my lights to LED bulbs, its a bit cold in my office. A new, hotter CPU could be just what I need.

You're confusing temperature and heat. A candle burns hotter than a person, but a person puts out more heat (100W) than a candle (80W). Likewise, Ivy Bridge puts out less heat than Sandy Bridge, even though it's hotter.