Broadwell cuts both ways. Broadwell is better than Haswell by 5 percent to 10 percent or so on a given task when the CPU models are exactly the same. Battery life is better by 10 percent or so. Graphics performance is much improved, but it's still just integrated graphics, best suited for office dronage or low-ambition gaming.
If you were to buy a laptop today, Broadwell is the way to go--if your options are between a Broadwell-based CPU and a Haswell-based one at the same price.
If you have a Haswell-based laptop, however, there's no point in upgrading to Broadwell. I don't expect that many people who bought a Haswell-based laptop in 2014 are deciding to upgrade to one with a Broadwell CPU a year later just for the CPU. They might upgrade for pen support, a better screen or a larger SSD or keyboard, however.
This information is really aimed at those using even older, 2nd-generation Sandy Bridge CPUs or 3rd-generation Ivy Bridge CPUs. Moving to a modern Broadwell laptop would deliver significant improvement in battery life and clock-for-clock performance, not to mention all of the other advances in screen quality, touch and SSD support. For those replacing an older laptop, Broadwell is the better CPU, and our tests prove it.
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