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Intel's Haswell: Optimized For Mobility
Date: Jun 04, 2013
Author: Joel Hruska
Introduction, Optimization
If Haswell's debut on the desktop has left you feeling a bit flat, the company's mobile efforts may be the pick-me-up you've been hoping for. If you step back and think about the entire CPU market, the last two years have been marked by tremendous shifts in consumer buying habits, as tablet sales skyrocketed and desktop/laptop sales have slumped. Intel recognized years ago that Atom, no matter how polished, would never be able to address the entire portable market -- the usage scenarios between a laptop and a smartphone are just too wide. The company therefore decided to take a two-pronged approach to this brave new frontier of computing, with a new Atom architecture anchoring the ultra-low power segments while more traditional x86 cores were prepped for form factors no one at Intel dreamed of ten years ago.

Some of the reasons Haswell is less exciting on the desktop, in other words, is because Intel prioritized a mobile architecture that would draw as little power as possible, while still offering excellent performance. Companies like Intel have a phenomenal degree of control over their hardware, but each fab line is tuned to different characteristics. CPUs that have been optimized for very low leakage and long standby times don't tend to clock as high as chips designed to operate at high frequencies.

Intel's battery life advances, however, come with a grain of salt. According to the fine print, the Core i7-4650U is 17% slower than the Core i7-3667U (1.7GHz base / 3.2GHz Turbo, compared to 2GHz / 3.2GHz for the Core i7-3667U). The newer system uses a monitor with a panel self refresh -- meaning that the monitor doesn't need to be redrawn every single cycle. Intel has been touting this technology as a power-saving measure for quite some time, but only one of these systems uses it.

The 3667U system also uses twice the RAM of the 4650U -- 4GB vs. 8GB. That doesn't mean that the Haswell platform doesn't use less power, but these are factors Intel could have controlled for in its comparison -- and didn't.

We should also mention that the figures given above don't match the improvements Intel lists in a more detailed breakdown. Here's stated power consumption in two different applications between unnamed IVB and Haswell hardware.

In this chart, Haswell draws 67% and 74% as much power as Ivy Bridge. Actual real-world gains in battery life are likely to fluctuate between the two claims, depending on how you use the system.
New Ultrabook Capabilities, Designs
Intel's major mobile push with ultrabooks is meant to simultaneously beef up design capabilities while cutting rated power consumption in two types of designs -- those that put processors in the base of the product (traditional laptops), and those that drop the CPU behind the screen (tablets, some convertibles).

 To make this happen, the company is introducing its new low-power Y-series with a Scenario Design Power (SDP) of 6W. SDP is a new metric that measures platform power consumption in tablet workloads and uses different metrics to establish a lower figure.

Santa Clara is also expanding ultrabook requirements and baseline capabilities. WiDi (Intel Wireless Display) is now a requirement, as are longer stand-by times, faster wake, mandatory antivirus protection, and a higher emphasis on ultra-thin designs. Intel's response to the market's low uptake of 2012's ultrabooks has been to double-down on the category and mandate an increasing number of features in the hopes of stoking customer interest.

One thing we can say about these new designs -- the high end ultrabooks aren't going to get much cheaper. The new 4650U that we discussed earlier has a list price of $454, compared to $346 for the Core i7-3667U. The new Core i5 version of that chip (1.4GHz - 2.6GHz) is $342, while third-generation Ivy Bridge 17W products are typically $225.

Intel's new Crystalwell graphics will also ship in the high-end mobile SKUs with 47W TDPs, where they should offer significantly improved GPU performance compared to previous Intel hardware combined with a lower total platform power draw. Reviews on the new Iris Pro 5200 solution shows that while it's still outperformed by higher-end NVIDIA hardware, the combination of Intel CPU + NVIDIA GPU draws significantly more power than the Iris Pro 5200 solution acting alone.  

Intel is claiming full 4K support for Iris Graphics, even over Intel WiDi, though some downscaling is almost certainly involved at that resolution. At this point, however, the topic is theoretical -- there aren't enough 4K panels to test the feature and it makes vastly more sense to stream a 1080p signal and upscale it at the television than to try and shove a 4K transmission over the air on a mobile power budget.

Haswell's Many SKUs

Intel is launching three sets of SKUs today -- the H-series, M-series, and U-series. This doesn't count the Y-series, which will debut later this month and features an SDP of around 6W. SKUs and prices are shown below.

For those of you who don't feel like digging through the sheets, the breakdown is this:  The H-series chips (middle image) are your mid-range Core i7's, with the fastest CPU cores and Iris Pro 5200 Graphics. All of these chips are quad-cores, with 37W - 47W TDPs. A few of them use HD 4600 rather than Iris Pro 5200, and the highest-end chip is $657.

The M-Series crosses the Core i5 / i7 / i3 boundary. The CPUs in this segment have faster clock speeds and weaker graphics. All of them feature HD 4600 GPUs and the top-end SKU is a 3GHz base clock / 3.8GHz turbo core with a $1096 price tag attached. The L3 cache is a max of 8MB, up from 6MB on the H-series processors.

The U-series is comprised of the low power chips. These dual cores are all 15W or less, with a wide range of graphics solutions. The family starts at $454, about $100 more than current IVB low-power processors.

There's a total of 37 SKUs before the lower-power Y-series parts have launched. If you're feeling a bit dizzied, don't worry -- so are we. Intel has created an enormous number of parts with subtle differences between them, presumably because OEMs and customers want a wide variety of potential product features.

Haswell's Time To Shine? 

Haswell's desktop unveil was a bit of a letdown for some people. The mobile data Intel has released suggests that these chips will deliver an increase in battery life and better overall thermals. Moving the voltage regulator on-die gives Intel greater flexibility to control CPU power use and sleep states, and the bevy of new ultrabook features should result in sexier high-end systems.

The degree to which these improvements will trickle down into the mainstream consumer market in 2013 is unclear; Intel recently announced that future Celeron and Pentium systems will be based on Atom hardware. That says good things about the 22nm Atom processor and its ability to hit mainstream performance targets, but it also implies that Intel wants to create a luxury brand around ultrabooks that keeps their own margins high.

That trend flies in the face of repeated OEM calls to bring ultrabook prices down. Given the way the PC OEMs have collectively failed to create positive brand experiences around their own products, we're not surprised that they rely on price to move volume, or that Intel would want to buck pricing demands to keep its margins high. Nevertheless, this isn't great news for customers who were hoping to spend less than $800 on a notebook and walk away with a next-generation ultrabook experience. The high chip prices and suite of new capabilities strongly implies that ultrabooks will remain luxury products in 2013 -- if you want to see what Haswell can really do in this form factor, you're going to pay for it. More mainstream notebooks featuring Haswell-based 4th Generation Core processors, however, should offer increased performance and battery life in more desirable form factors.

We'll have more for you in the coming days and weeks as Haswell-based notebooks arrive in the lab.  We've already gone one machine on the bench and more are sure to follow.

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