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CES has always been a major launch window for Intel and 2015 was no exception. The company announced multiple new Broadwell chips today, as it’s been promising to do for the past few years — but exactly which cores are these, and how much should you care about them compared to the Haswell chips currently on the market?

First, let’s back up to how Broadwell’s initial delays impacted the long-term product rollout. When Intel decided to stagger Broadwell’s launch dates, it opted to introduce the most power-efficient cores first, followed by mobile parts in the 5-28W TDP range. The new chips are known as Broadwell-U, to distinguish them from the Core M family (Broadwell-Y).

These new core are going to replace the current crop of Haswell low voltage and mainstream dual-core processors, and primarily drop into ultrabooks and non-enthusiast laptops. The advance are driven by two different cores — an uprated 1.3B Core M chip with higher TDPs and correspondingly more powerful clocks.



The other Broadwell variant, shown above, bumps up the transistor count and die size considerably, mostly on the GPU side of the equation. Broadwell-U’s 1.9B transistors are spent pushing out the GPU to 48 executable units, up from the 24 EUs*in Broadwell-Y/Core M. In Intel’s parlance, an “EU” or execution unit, is the fundamental unit of the graphics engine — 48 EUs is equivalent to the CUDA core count or streaming processor count from an Nvidia or AMD chip (note: GPU core counts cannot be compared directly due to drastic differences in how much work each “core” can perform per cycle).



Broadwell’s GPU is available in two basic configurations — GT3 (48 EUs) and GT2 (24 EUs). GPU horsepower is the major factor in determining Intel’s hardware stack and processor pricing. The company is releasing the same basic dual-core + Hyper-Threading CPU in multiple GPU configurations and TDPs, including:

• Intel Iris Graphics 6100 (GT3 graphics, 28W TDP)
• Intel HD Graphics 6000 (GT3 graphics, 15W TDP)
• Intel HD Graphics 5500 (GT2 graphics, 15W TDP)
• Intel HD Graphics (Pentium and Celeron, 15W TDP)

The “HD Graphics” denotes a cut-down subsystem with minimal performance attached to a low-cost processor. Graphics capability plays an important role in both chip TDP and Intel’s pricing — the cheapest HD 6000 parts start at $315 for 15W parts, while the slightly higher-clocked Iris 6100 chips at 28W TDPs are the same price.

Will Broadwell boost battery life?

The big question for mobile users is going to be whether Broadwell will improve battery life. The picture there is complicated — it very much depends on where you look and what you’re looking for. On the positive side, Broadwell incorporates multiple improvements to the underlying SoC, over and above the improved 14nm process. Intel can now turn the GPU off for much of the time (while continuing to refresh the display controller). In addition, Broadwell sports a new, low-power audio DSP that improves power consumption while watching movies or playing back certain types of content.
Previous research, however, has shown that these kinds of gains are very much conditional. When Haswell shipped, DigitalTrends did a comparison study on how an identical laptop with Haswell performed in various battery life scenarios compared to Ivy Bridge. In near-idle tests, Haswell indeed delivered a nearly 50% increase in battery life.



In other scenarios, however, the gains were much more modest, and at full power load, battery life actually went backwards. This reflects underlying physics rather than skullduggery on Intel’s part, but it’s important to keep in mind that the improvements you see are going to be workload dependent.

The second complicating factor is laptop manufacturer’s tendency to suck up efficiency improvements through the use of higher-end hardware and the relentless pursuit of thinner form factors and lighter systems. Again, there’s nothing objectively wrong*with that, but higher resolution displays consume more power than lower ones, assuming equal technology. Smaller, lighter laptops tends to mean smaller, thinner batteries. In some cases, this also means a reliance on USB charging, which can exacerbate the battery issue by taking longer to recharge the system.

Put together, we’d suggest that end users expect to evaluate Broadwell system-by-system and in specific use cases. There will undoubtedly be scenarios where it substantially improves on Haswell — and there are going to be laptops that don’t show much gain at all, for a variety of reasons.

Overall, Broadwell is going to be a positive step forward for the mobile PC industry and if you’re upgrading from a laptop from the 2010-2011 era, I’d jump on it, no question. If you’re already using Ivy Bridge or Haswell, however, I’d wait to see what specific systems offer and evaluate the various pros and cons of hardware configurations. Lower resolution displays and heavier batteries may not be as sexy as Retina-class hardware and featherweight products, but for some people, the battery life improvements outweigh the other issues.


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