Power Improvements

Although Haswell’s platform power is expected to drop considerably in mobile, particularly with Haswell U and Y SKUs (Ultrabooks and ultrathins/tablets), there are benefits to desktop Haswell parts as well.

There’s more fine grained power gating, lower chipset power and the CPU cores can transition between power states about 25% quicker than in Ivy Bridge - allowing the power control unit to be more aggressive in selecting lower power modes. We’ve also seen considerable improvements on lowering platform power consumption at the motherboard level as well. Using ASUS’ Z77 Deluxe and Z87 Deluxe motherboards for the Haswell, Ivy and Sandy Bridge CPUs, I measured significant improvements in idle power consumption:

Idle Power

These savings are beyond what I’d expect from Haswell alone. Intel isn’t the only one looking to make things as best as can be in the absence of any low hanging fruit. The motherboard makers are aggressively polishing their designs in order to grow their marketshare in a very difficult environment.

Under load, there’s no escaping the fact that Haswell can burn more power in pursuit of higher performance:

Load Power - x264 HD 5.0.1 Benchmark

Here I’m showing an 11.8% increase in power consumption, and in this particular test the Core i7-4770K is 13% faster than the i7-3770K. Power consumption goes up, but so does performance per watt.

The other big part of the Haswell power story is what Intel is calling FIVR: Haswell’s Fully Integrated Voltage Regulator. Through a combination of on-die and on-package circuitry (mostly inductors on-package), Haswell assumes responsibility of distributing voltages to individual blocks and controllers (e.g. PCIe controller, memory controller, processor graphics, etc...). With FIVR, it’s easy to implement tons of voltage rails - which is why Intel doubled the number of internal voltage rails. With more independent voltage rails, there’s more fine grained control over the power delivered to various blocks of Haswell.

Thanks to a relatively high input voltage (on the order of 1.8V), it’s possible to generate quite a bit of current on-package and efficiently distribute power to all areas of the chip. Voltage ramps are 5 - 10x quicker with FIVR than with a traditional on-board voltage regulator implementation.

In order to ensure broad compatibility with memory types, there’s a second input voltage for DRAM as well.

FIVR also comes with a reduction in board area and component cost. I don’t suppose this is going to be a huge deal for desktops (admittedly the space and cost savings are basically non-existent), but it’ll mean a lot for mobile.

No S0ix for Desktop

You’ll notice that I didn’t mention any of the aggressive platform power optimizations in my sections on Haswell power management, that’s because they pretty much don’t apply here. The new active idle (S0ix) states are not supported by any of the desktop SKUs. It’s only the forthcoming Y and U series parts that support S0ix.

Introduction Memory, Platform & Overclocking
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  • Iketh - Sunday, June 02, 2013 - link

    Your post is so ignorant that you should have posting privileges revoked. Reply
  • gryer7421 - Monday, June 03, 2013 - link

    ? Everyone knew this was intels piledriver revision. Reply
  • Donkey2008 - Monday, June 03, 2013 - link

    When you are "cynical" you will "see" nothing "good" in anything. Reply
  • jonjonjonj - Tuesday, June 04, 2013 - link

    i agree. its annoying that intel is designing their desktop cpu's to also compete with arm in mobile. why can't intel develop 2 different versions or architectures? is power efficiency the limiting factor and if TDP and power was no concern how much better could intel do?

    i personally don't care about power on my desktop as long as the performance justifies it. desktop cpu's should be about performance not saving power.
    Reply
  • Death666Angel - Tuesday, June 04, 2013 - link

    How can you be disappointed when Haswell gives you exactly what was promised? It seems like you should have adjusted your expectations. Or you just like to be disappointed.

    I'm not surprised by these numbers, they are what was expected. I'm still running an i7-860 @3.8GHz and when I get enough money I'll upgrade to an i7-4770k and hopefully be able to run it at 4.5GHz, give or take some (water cooling setup here). Maybe IVB-E if it tests well and money is not too tight.

    Anand really needs a Lynnfield for comparisons, because the i7-9xx was geared towards people running the enthusiast platform, whereas all the other CPUs tested here are geared towards mainstream high end.
    Reply
  • ninjaquick - Wednesday, June 05, 2013 - link

    Haswell at 1.8 GHz is a completely different story to any of this... Mark my words: You will never see 3.4 GHz parts in tablets, ever.

    However, a 30% improvement in efficiency can be roughly translated to a 30% increase in performance per watt. That is massive in tablets.

    Sure, it won't be a 3.4 GHz tablet part, but it will also be a bit quicker than a 1.6 GHz tablet part.
    Reply
  • mkygod - Wednesday, September 18, 2013 - link

    Of course they are comparing to older CPUs because the article made a point to say that it does not make a whole lot of sense to upgrade from Ivy Bridge. But still, 5-10% faster compared to Ivy bridge is pretty good i would say for the extra ~$10-20 dollar difference. Reply
  • boe - Monday, June 03, 2013 - link

    Its just as good as ivy bridge - pretty much ivy bridge pretending to be something new. Reply
  • Dnann - Friday, June 14, 2013 - link

    It seems that not as good as I was imagining. :O Reply
  • rudolphna - Saturday, June 01, 2013 - link

    Honestly, the best part of the review was the comparisons to older chips. It's entertaining to see just how terrible the Pentium 4 was in hindsight. Reply

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